Systemic Amyloidosis Insights by Cardiovascular …...Dr Sanjay M. Banypersad MD (Res) Thesis UCL...
Transcript of Systemic Amyloidosis Insights by Cardiovascular …...Dr Sanjay M. Banypersad MD (Res) Thesis UCL...
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Systemic Amyloidosis – Insights by
Cardiovascular Magnetic Resonance
By
Dr Sanjay M. Banypersad
MD (Res) Thesis
UCL
2015
UCL INSTITUTE OF CARDIOVASCULAR SCIENCE
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1. Declaration
I, Sanjay Mahesh Banypersad, confirm that the work presented in this thesis is my own.
Where information has been derived from other sources, I confirm that this has been
indicated in the thesis
Signature: (electronically signed)
Name: Sanjay M. Banypersad Date: 13th April 2015
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2. Abstract
Systemic amyloidosis is the exemplar infiltrative, extracellular disease. Although it is
a multi-organ disorder, cardiac involvement drives prognosis. Survival is worst in the AL
amyloidosis subtype. It can affect any age and any race. There is no direct test for amyloid
burden and there is no treatment for amyloidosis, there is only treatment for the underlying
condition. Earlier diagnosis permits prompt treatment and improves survival.
A number of imaging modalities exist to non-invasively detect cardiac disease but all
have limitations. Cardiovascular magnetic resonance (CMR) with late gadolinium
enhancement (LGE) imaging provides the highest sensitivity for early detection. However,
this also has its shortcomings. There is currently no non-invasive method of directly
measuring amyloid burden in the extracellular space. New therapies are pending – but their
development needs new surrogate endpoints and new tests are therefore desperately
needed. T1 mapping permits tissue abnormalities to be directly visualised in a simple scan –
the colour changes being instantly recognisable, either before contrast (pre contrast or
native T1 mapping) or after, when the myocardial extracellular volume (ECV) can be
measured.
In a collaboration between the National Amyloidosis Centre and the Heart Hospital, I
explored the possibility and potential that T1 mapping might measure cardiac (and other
organ) involvement in systemic amyloidosis using EQ-MRI.
In early clinical exploration in systemic AL amyloid, I showed that native myocardial
T1 was elevated in cardiac amyloidosis and tracked disease, particularly early disease. Mean
pre contrast myocardial T1 as measured by ShMOLLI was higher in patients at 1086 ±
90msec, compared to healthy volunteers of 958 ± 20msec (P<0.001). Myocardial T1 times
showed a stepwise elevation as the probability for cardiac involvement increased: 1009 ±
31msec without cardiac involvement, 1048 ± 48msec with possible cardiac involvement,
1140 ± 61msec with definite cardiac involvement (P<0.001).
Using contrast to measure the ECV, I was able to non-invasively and directly measure
the amyloid burden in the heart for the first time. Mean cardiac ECV was greater in patients
compared to healthy volunteers with a wider range (0.44 ± 0.12 vs 0.25 ± 0.02, P<0.001) and
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tracked pre-test probability of cardiac involvement by conventional parameters (P<0.001).
ECV also tracked conventional measures of disease severity and correlated with survival
with a median ECV of 0.45 being the best model for assessing survival: HR 3.84 (1.53 – 9.61),
P=0.004. I demonstrated good reproducibility of the technique with an ICC of > 0.9 for both
the FLASH IR and ShMOLLI techniques of T1 mapping and good agreement of ECV derived
from both techniques. In pilot studies, I also demonstrated by serial scanning that changes
(including regression) over time could be measured.
In other organs, I showed that the amyloid burden could be measured and was
higher in amyloidosis compared to healthy volunteer: ECV 0.32 vs 0.29 (P<0.001) for liver,
0.39 vs 0.34 (P<0.001) for spleen and 0.16 vs 0.09 (P<0.001) for skeletal muscle. These ECVs
also tracked current conventional measures of disease severity by nuclear scintigraphy.
These results demonstrate that the interstitial volume in patients with systemic AL
amyloidosis can be measured non invasively in the heart, liver, spleen and skeletal muscle
and that this correlates with existing markers of disease and survival. Pre contrast
myocardial T1 was a good alternative measure for the heart.
In conclusion, the work in this thesis has enabled a deeper understanding of cardiac
amyloidosis, disease processes and stages. It has pioneered a new prognostic marker that is
also able to identify some patients with cardiac involvement that were previously
unrecognised. Novel subtypes are now recognised (e.g. cardiac amyloidosis with no LVH)
and it has also allowed direct quantification of the liver and spleen. ECV is a new and
powerful biomarker that has already been adopted by industry allowing development of
new therapies and providing hope that an end to the scourge of this disease is near.
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3. Abbreviations
6MWT 6 Minute Walking Test
AA Amyloid (serum amyloid A)
ACE-i Angiotensin Converting Enzyme inhibitor
AF Atrial Fibrillation
AFD Anderson Fabry’s disease
AHA American Heart Association
AL Amyloid Light-chain
ANOVA Analysis of Variance
ANP Atrial Natriuretic Peptide
ApoA1 Apolipoprotein A1
ARB Angiotensin Receptor Blocker
AS Aortic stenosis
ASCT Autologous Stem Cell Transplant
ATTR Amyloid Transthyretin
AV Atrioventricular
AVR Aortic Valve Replacement
BCS British Cardiovascular Society
BHF British Heart Foundation
BNP Brain Natriuretic Peptide
BP Blood Pressure
CI Confidence Intervals
CMR Cardiovascular Magnetic Resonance
CPHPC R-1-[6-[R-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl] pyrrolidine-2-carboxylic acid
CR Complete (light chain) Response
CSF Cerebrospinal Fluid
CT Computed Tomography
CTD Cyclophosphamide, Thalidomide (and) Dexamethasone
CVD Cyclophosphamide, Velcade (and) Dexamethasone
DCM Dilated Cardiomyopathy
DNA Deoxyribonucleic Acid
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DOTA 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid
DPD 3,3-diphosphono-1,2-propanodicarboxylic acid
ECG Electrocardiogram
ECOG Eastern Cooperative Oncology Group
ECV Extracellular Volume
ECVb Extracellular Volume (bolus only method)
ECVi Extracellular Volume (infusion method)
EF Ejection Fraction
eGFR Estimated Glomerular Filtration Rate
EMG Electromyogram
EQ-CMR Equilibrium (contrast) Cardiovascular Magnetic Resonance
FAP Familial Amyloid Polyneuropathy
FISP Fast Imaging with Steady State Precession
FLASH (IR) Fast Low Angle Shot (Inversion Recovery)
FOV Field of View
GAGS Glycosaminoglycans
GE General Electric
GI Gastrointestinal
GSK Glaxo Smith Kline
HCM Hypertrophic Cardiomyopathy
HR Hazard Ratio
IBM International Business Machine (Corporation)
ICC Intraclass Correlation Coefficient
ICD Implantable Cardioverter Defibrillator
IQ Interquartile (range)
IVRT Isovolumic Relaxation Time
KM Kaplan Meier
LA Left Atrium
LAA Left Atrial Area
LBBB Left Bundle Branch Block
LGE Late Gadolinium Enhancement
Ln Natural logarithm
LV Left Ventricle
LVEDV(i) Left Ventricular End Diastolic Volume (indexed)
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LVESV(i) Left Ventricular End Systolic Volume (indexed)
LVH Left Ventricular Hypertrophy
MAPSE Mitral Annular Plane Systolic Excursion
MGUS Monoclonal Gammopathy (of) Undetermined Significance
MI Myocardial Infarction
MOLLI Modified Look Locker Inversion (recovery)
MRI Magnetic Resonance Imaging
msec Milliseconds
mV Millivolts
NAC National Amyloidosis Centre
NHS National Health Service
NNE Nearest Neighbour Estimator
NT-proBNP Nitrogen-Terminal Brain Natriuretic Peptide
NYHA New York Heart Association
PET Positron Emission Tomography
PR Partial (light chain) Response
PSIR Phase Sensitive Inversion Recovery
REDCap Research Electronic Data capture
RF Radiofrequency
RNA Ribonucleic acid
ROC Receiver Operating Characteristic
ROI Region of Interest
RV Right Ventricle
SAA Serum Amyloid A
SAP Serum Amyloid P
SASHA Saturation-recovery Single-shot Acquisition
SCMR Society (of) Cardiovascular Magnetic Resonance
SD Standard Deviation
ShMOLLI Shortened Modified Look Locker Inversion (recovery)
SPECT Single Photon Emission Computed Tomography
SPSS Statistical Package (for the) Social Sciences
SSA Senile Systemic Amyloidosis
SSFP Steady State Free Precession
TAPSE Tricuspid Annular Plane Systolic Excursion
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TD Trigger delay
TDI Tissue Doppler Imaging
TE Echo Time
TI Inversion Time
TNF Tumour Necrosis Factor
TR Repeat Time
TTR Transthyretin
VIF Variance Inflation Factor
VT Ventricular Tachycardia
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4. Contents
Chapter Page
1 Declaration 2
2 Abstract 3
3 Abbreviations 5
4 Contents 9
4.1 Figures 15
4.2 Tables 17
5 Aims and Objectives 18
6 Introduction 19
6.1 What is Amyloidosis? 19
6.2 What is Systemic Amyloidosis? 20
6.3 Cardiac Disease in Amyloidosis 23
6.3.1 AL Amyloidosis 23
6.3.2 Hereditary (ATTR) Amyloidosis 24
6.3.3 Senile Systemic Amyloidosis 25
6.3.4 Other types of cardiac amyloidosis 26
6.4 Diagnosis 26
6.4.1 ECG 26
6.4.2 Echocardiography 28
6.4.3 Cardiac biomarkers 29
6.4.4 Radionuclide Imaging 30
6.4.5 Cardiac MRI 31
6.4.6 Endomyocardial biopsy 33
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6.5 Liver and Spleen in Systemic Amyloidosis 34
6.6 Skeletal muscle in Systemic Amyloidosis 35
6.7 Prognosis 35
6.8 Treatment 36
6.8.1 Non Amyloid Specific 36
6.8.1.1 Heart Failure Therapy 36
6.8.1.2 Device Therapy 36
6.8.1.3 Cardiac Transplantation 37
6.8.2 Amyloid Specific 37
6.8.2.1 Reducing Amyloid Fibril Precursor Protein Production 37
6.8.2.2 Inhibition of Amyloid Formation 39
6.8.2.3 Targeting Amyloid Deposits by Immunotherapy 40
6.9 Measuring Interstitial Expansion using MRI 41
6.9.1 MRI General Physics 41
6.9.2 T1 mapping 43
6.10 Equilibrium cardiovascular magnetic resonance 45
7 Methods 52
7.1 Ethical approval 52
7.2 Patients 52
7.3 Healthy Volunteers 54
7.4 CMR 54
7.4.1 Pilot Images 54
7.4.2 Cine Imaging 55
7.4.3 Pre contrast T1 assessment 55
7.4.3.1 FLASH Heart 55
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7.4.3.2 FLASH Liver, Spleen and Skeletal Muscle 56
7.4.3.3 ShMOLLI Heart, Liver and Spleen 57
7.4.4 LGE Imaging 57
7.4.5 Post Contrast T1 Evaluation 58
7.4.6 Off line Analysis 58
7.5 Blood pressure and ECG 58
7.6 Blood Tests 59
7.7 6 minute walk testing 59
7.8 Echocardiography 59
7.9 SAP scintigraphy 59
7.10 DPD scintigraphy 60
7.11 Statistical Analysis 60
8 Results: Myocardial ECV as measured by EQ-CMR in Systemic AL Amyloidosis 63
8.1 Introduction 63
8.2 Hypotheses 64
8.3 Methods 64
8.4 Results 66
8.5 Discussion 72
8.6 Conclusion 74
9 Results: Extracardiac ECV as measured by EQ-CMR in Systemic AL Amyloidosis 75
9.1 Introduction 75
9.2 Hypotheses 76
9.3 Methods 76
9.4 Results 76
9.5 Discussion 78
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9.6 Conclusion 81
10 Results: Technical Development – Refining Clinical Applicability 82
10.1 Introduction 82
10.2 Hypotheses 84
10.3 Methods 84
10.4 Results 84
10.5 Discussion 87
10.6 Conclusion 88
11 Results: Pre Contrast T1 Mapping in Systemic AL Amyloidosis 89
11.1 Introduction 89
11.2 Hypotheses 90
11.3 Methods 90
11.4 Results 91
11.5 Discussion 95
11.6 Conclusion 97
12 Results: T1 Mapping and Survival in Systemic AL Amyloidosis 98
12.1 Introduction 98
12.2 Hypotheses 98
12.3 Methods 99
12.4 Results 100
12.5 Discussion 108
12.6 Conclusion 110
13 Results: Pilot Study – Follow up in AL Amyloid 111
13.1 Introduction 111
13.2 Hypotheses 111
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13.3 Methods 112
13.4 Results 112
13.5 Discussion 115
13.6 Conclusion 117
14 Discussion and Conclusions 118
14.1 Background and hypothesis explored 118
14.2 Technical development 119
14.3 ECV 120
14.4 Native T1 mapping 120
14.5 Clinical insights 121
14.6 Future work 122
14.7 Conclusions 123
15 References 124
16 Appendix 143
16.1 Acknowledgements 143
16.2 List of original findings 145
16.3 Location of research 145
16.4 Personal contribution 145
16.5 Supervision 146
16.6 Funding 146
16.7 Prizes / Awards 146
16.8 Publications 146
16.9 Abstract presentations 149
16.9.1 Oral Presentations 149
16.9.2 Poster Presentations 149
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16.9.3 Named-author Abtracts Presented by Others 150
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Figures & Tables
4.1 Figures Page
Figure 1: Cardiac biopsy in AL Amyloidosis 20
Figure 2: ECG appearances in cardiac amyloidosis 27
Figure 3: Speckle tracking in cardiac amyloidosis 28
Figure 4: DPD imaging in ATTR amyloidosis 31
Figure 5: Global subendocardial LGE in cardiac amyloidosis 32
Figure 6: Alternative LGE appearances on CMR in cardiac amyloidosis 32
Figure 7: Post gadolinium TI scout appearances in cardiac amyloidosis 33
Figure 8: SAP scan image in AL and ATTR amyloidosis 34
Figure 9: SAP scan image in AA amyloidosis 35
Figure 10: Diagram illustrating mode of action of CPHPC and antibody 41
Figure 11: MRI recovery curve demonstration T1 times 42
Figure 12: Graph showing changes in gadolinium concentration with time in
myocardium and blood 43
Figure 13: Pre contrast TI scout in cardiac amyloidosis 43
Figure 14: Schematic showing recovery curves in ShMOLLI 44
Figure 15: ShMOLLI image in normals and amyloidosis 45
Figure 16: FLASH T1 measurement for heart 46
Figure 17: Graph showing change in signal intensity with TI 46
Figure 18: Graph showing change in TI with time with and without infusion 47
Figure 19: Graph showing change in signal intensity with TI for myocardium
and blood pre and post contrast administration 48
Figure 20: Graph showing correlation of ECV with collagen in AS 49
Figure 21: Mean ECV in various cardiac diseases 50
Figure 22: FLASH T1 measurement for liver, spleen and muscle 56
Figure 23: Pie chart of biopsies for AL amyloidosis patients 65
Figure 24: Difficulty avoiding LGE when drawing ROI in T1 measurement 66
Figure 25: Relationship of ECV with pre-test probability of cardiac amyloidosis 68
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Figure 26: Graphs showing relationship of ECV with LV structure 69
Figure 27: Graphs showing relationship of ECV with LV function 69
Figure 28: Graphs showing relationship of ECV with ECG and biomarkers 70
Figure 29: Graphs showing ECV of liver, spleen and muscle 77
Figure 30: Liver, spleen and muscle ECV with SAP grade 78
Figure 31: FLASH vs ShMOLLI reproducibility for cardiac ECV 85
Figure 32: FLASH vs ShMOLLI reproducibility for liver ECV 85
Figure 33: FLASH vs ShMOLLI reproducibility for spleen ECV 86
Figure 34: ECVi vs ECVb correlation and agreement 86
Figure 35: Interstudy reproducibility for cardiac ECV using ShMOLLI 87
Figure 36: Pie chart of biopsies for AL amyloidosis patients in native
myocardial T1 chapter 90
Figure 37: Relationship of T1 with pre-test probability of cardiac amyloidosis 92
Figure 38: ROC curve analysis for T1 and amyloidosis 93
Figure 39: Typical appearances of T1 map and LGE in amyloidosis 94
Figure 40: Relationship of T1 with markers of cardiac amyloidosis 95
Figure 41: Pie chart of biopsies for AL amyloidosis patients in T1 mapping
and survival chapter 99
Figure 42: Dot plot showing correlation between ECV and late gadolinium
enhancement 103
Figure 43: Kaplan Meier survival curve for ECVi 105
Figure 44: Kaplan Meier survival curve for ECVb and T1 105
Figure 45: Time-dependent ROC curves for ECV and pre contrast myocardial T1
at 12 and 24 months using the NNE method 106
Figure 46: Time-dependent ROC curves for ECV and pre contrast myocardial T1
at 24 months using the KM method 107
Figure 47: Scatter plot of changes for ECV with treatment 114
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4.2 TABLES:
Table 1: Pathology, presentation and management of different amyloid types 22
Table 2: Patient baseline characteristics for ECV using FLASH EQ-CMR chapter 67
Table 3: Pearson’s correlations for myocardial ECV (FLASH) with cardiac measures 71
Table 4: Patient baseline characteristics for native myocardial T1 chapter 91
Table 5: Native myocardial T1 results and diastolic measures for AL patients 95
Table 6: Patient baseline characteristics for T1 mapping and survival chapter 101
Table 7: Correlations for ECV, native & post contrast T1 with cardiac measures 102
Table 8: Hazard ratios and Harrell’s C statistic for ECV, native & post contrast T1 104
Table 9: Hazard ratios from univariate analyses of multiple variables with mortality 107
Table 10: Hazard ratios from multivariable analysis 108
Table 11: ECV and other parameter changes from baseline to follow up 113
Table 12: Difference in amyloid mass and cell mass from baseline to follow up 115
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5. Aims & Objectives
This thesis investigates the use of novel methods in cardiovascular magnetic
resonance (CMR) for the investigation of the extracellular space of multiple organs in
systemic amyloidosis. As in all science, it is built on the work of others – key methods were
developed at Heart Hospital by my colleagues: (a) Dr Andrew Flett (UCL MD (Res), 2012)
who designed and validated the use of EQ-CMR to measure myocardial fibrosis in aortic
stenosis and hypertrophic cardiomyopathy; and (b) Dr. Daniel Sado (UCL MD (Res), 2013)
who explored the role of ECV measurement (again for fibrosis) across a variety of cardiac
diseases. My thesis built on this, but in amyloidosis.
The aims are:
1) To investigate new potential markers of myocardial abnormality - ECV and native
myocardial T1 measurement in cardiac amyloidosis, comparing the results to other
clinical markers of disease severity.
2) To translate these methods to other organs - the liver, spleen and skeletal muscle in
patients with systemic amyloidosis.
3) To improve ECV and T1 measurement techniques in CMR allowing quicker, more
reproducible assessment for clinical delivery and as a surrogate endpoint for clinical
trials
4) To create new hypotheses and aid in the recruitment and training of new
researchers to continue this work, concurrently presenting and publishing the
results, with the overall aim of bringing therapy and understanding of amyloid a step
closer for patients; a step closer to improved outcomes for patients.
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6. Introduction
This chapter is based on the publication below:1
Banypersad SM, Moon JC, Whelan C, Hawkins PN, Wechalekar AD. Updates in cardiac
amyloidosis: a review. J Am Heart Assoc. 2012 Apr;1(2):e000364
My contribution was to research the material and write the paper.
6.1 WHAT IS AMYLOIDOSIS?:
Amyloidosis is a generic term that refers to the extracellular deposition of
autologous protein in an abnormal, insoluble β-pleated sheet, fibrillary conformation i.e. as
amyloid fibrils. More than 30 proteins are known to be able to form amyloid fibrils in vivo,
which cause disease by progressively damaging the structure and function of affected
tissues.2 Amyloid deposits also contain minor non-fibrillary constituents including serum
amyloid P component (SAP), apolipoprotein, connective tissue components such as
glycosaminoglycans (GAGS) and collagen, and basement membrane components such as
fibronectin and laminin.3-7 Amyloid deposits can be massive and cardiac or other tissues may
become substantially replaced.
Amyloid fibrils bind Congo red stain, yielding the pathognomonic apple-green
birefringence under cross-polarized light microscopy that remains the gold standard for
identifying amyloid deposits. Further staining with immunohistochemistry is performed to
subtype into the 2 main types which affect ventricular myocardium, light chain amyloid (AL)
and transthyretin amyloid (ATTR) (see figure 1).
Data regarding the molecular mechanisms at work in the extracellular space is
rapidly accumulating. Autopsy studies of ventricular myocardium reveal homogeneous,
eosinophilic deposits separating the muscle fibres and amorphous hyaline deposits that are
predominantly seen in the expanding extracellular space.8 Molecular chaperones, such as
clusterins, have been found to be over-represented in electron-microscopy analysis of
cardiac biopsies in both AL and ATTR Amyloidoses.9
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Figure 1: An endomyocardial biopsy of a patient with cardiac AL amyloidosis stained as follows: (A) Congo Red only; (B) Apple-green birefringence under cross-polarized light; (C) Congo Red with lambda overlay (negative); (D) Congo Red with kappa overlay (positive).
Studies of matrix metalloproteinases and their tissue inhibitors have suggested a
direct effect of the activation of proteolysis in the extracellular matrix by circulating
immunoglobulin light chains.10 This may explain the long recognised observation that in
primary AL amyloidosis, even mild to moderate ventricular thickening can cause significantly
debilitating symptoms whereas the patient with an equivalent wall thickness in ATTR
amyloid is often asymptomatic.11
6.2 WHAT IS SYSTEMIC AMYLOIDOSIS?:
Systemic amyloidosis is the exemplar of a purely extracellular disease; it is a
relatively rare multisystem disease caused by the deposition of misfolded protein in various
tissues and organs, causing organ dysfunction through interstitial expansion. It may present
to almost any specialty and diagnosis is frequently delayed.12 There are several different
types of amyloid. As previously mentioned, the ventricles are primarily affected by AL and
ATTR types; ATTR amyloid is further sub-divided into Senile Systemic Amyloidosis (SSA) and
variant ATTR (see sections 6.3.2 and 6.3.3 later in this thesis).
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Clinical phenotype varies greatly between different types of amyloidosis, and even
the cardiac presentation has a great spectrum. The incidence of amyloidosis is uncertain,
but it is thought that the most frequently diagnosed type, AL amyloidosis, has an annual
incidence of 6-10 cases per million population in the UK and US. Wild type transthyretin
(TTR) amyloid deposits, which predominantly accumulate in the heart, are very common at
autopsy in the elderly and whilst the associated clinical syndrome known as senile systemic
amyloidosis is diagnosed rarely in life,13 there is increasing evidence that this disorder is
much under-diagnosed, and that with increasing longevity and improved diagnostic
methods, it may be identified as a substantial public health problem.
Key ‘red flags’ to the diagnosis of possible systemic amyloidosis include: nephrotic
syndrome, autonomic neuropathy (postural hypotension, diarrhoea), soft tissue infiltration
(macroglossia, carpal tunnel syndrome), cutaneous bleeding (periorbital, gastrointestinal),
malnutrition/cachexia and genetic predisposition (family history/ethnicity). Other organ
involvement, particularly in AL amyloidosis, may cloud the cardiac presentation (nephrotic
syndrome, autonomic neuropathy, pulmonary or bronchial involvement). Table 1 on the
next page gives an outline of the clinical phenotype of the common amyloid subtypes.
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Amyloid type Precursor
protein
Typical decade
of presentation
Cardiac
involvement
Other organ
involvement
Treatment Prognosis (median
survival)
Primary (AL)
Amyloidosis
Monoclonal
light chain
6th to 7th decade
(but can be any)
40-50% Renal, liver, soft tissue,
neuropathy
Chemotherapy or
ASCT
48 months but 8 months
for advanced stage disease.
Transthyretin Amyloidosis: consisting of:
Senile
Systemic (SSA)
Wild-type TTR 70 years Almost all cases carpal tunnel syndrome Supportive
7-8 years
ATTR (V30M) Variant TTR 3rd or 4th decade Uncommon Peripheral and autonomic
neuropathy
Liver transplantation Good with liver transplant
for V30M
ATTR (T60A) Variant TTR 6th decade Up to 90% by
diagnosis
Peripheral and autonomic
neuropathy
Liver transplant
possible in selected
Variable with liver
transplant
ATTR Ile 122 Variant TTR 6th – 7th decade Almost all cases carpal tunnel syndrome Supportive 7-8 years
Apolipoprotein A1
(ApoA1)
Variant
apolipoprotein
6th – 7th decade Rare Predominantly renal Renal (+/- liver)
transplant
Usually slowly progressive
(years)
Secondary (AA)
amyloidosis
Serum amyloid
A (SAA)
Any Rare Renal, liver Treat underlying
condition
Good
Atrial natriuretic
peptide (ANP)
ANP 70 years or older All cases (uncertain
significance)
None reported Not needed -
Table 1: summarising the pathology, presentation and management of different amyloid types
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6.3 CARDIAC DISEASE:
Ventricular cardiac involvement is a leading cause of morbidity and mortality,
especially in primary (AL) amyloidosis and in both wild type and hereditary transthyretin
amyloidosis. The heart is also occasionally involved in acquired AA amyloidosis, other rare
hereditary types, and there is a specific atrial subtype (ANP).
Cardiac amyloidosis affecting the ventricles, irrespective of type, presents as a
restrictive cardiomyopathy caused by interstitial expansion due to the amyloid and is
characterized by progressive diastolic and subsequently systolic biventricular dysfunction and
arrhythmia.12 Initial presentations may be cardiac with progressive exercise intolerance and
heart failure. Pulmonary oedema is not common early in the disease process,14 but pleural
and pericardial effusions and atrial arrhythmias are often seen.15, 16 Syncope is common and a
poor prognostic sign.17 It is typically exertional or post-prandial as part of either restrictive
cardiomyopathy, sensitivity to intravascular fluid depletion from loop diuretics combined with
autonomic neuropathy, or conduction tissue involvement (AV or sinus nodes) or ventricular
arrhythmia.18-20 The latter may rarely cause recurrent syncope.
Disproportionate septal amyloid accumulation mimicking hypertrophic cardio-
myopathy (HCM) with dynamic left ventricular outflow tract obstruction21-24 is rare, but well
documented. Myocardial ischaemia can result from amyloid deposits within the
microvasculature.25, 26 Atrial thrombus is common, particularly in AL amyloidosis, sometimes
before atrial fibrillation (AF) occurs.27 Intracardiac thrombus can embolise, causing transient
ischaemic attacks or strokes and may be an early or even presenting feature.28
Anticoagulation is therefore important in the appropriate clinical situation but careful
consideration has be given in patients with extensive systemic AL amyloidosis who may have
an elevated bleeding risk seen due to Factor X deficiency or in some cases with GI
involvement.29
6.3.1 AL Amyloidosis:
AL amyloidosis is caused by deposition of fibrils composed of monoclonal
immunoglobulin light chains, and is associated with clonal plasma cell or other B-cell
dyscrasias. The fibrils in AL amyloidosis are derived from the variable region of lambda light
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chains in approximately 75% of cases, and kappa in the remainder.30 In approximately 10% of
cases, the disorder overlaps with overt multiple myeloma.
The spectrum and pattern of organ involvement is very wide, but cardiac involvement
occurs in half of cases and is sometimes the only presenting feature.31 Cardiac AL amyloidosis
may be rapidly progressive. Low QRS voltages, particularly in the limb leads are common.
Thickening of the left ventricular wall is typically mild to moderate, and is rarely greater than
18mm, even in advanced disease. Cardiac AL amyloid deposition is accompanied by marked
elevation of the biomarkers brain natriuretic peptide (BNP, specifically NT-proBNP) and
cardiac troponin, even at an early stage. The right heart failure is often exacerbated by the
co-presence of nephrotic syndrome in 30-50% of cases.12 The hypoalbuminaemia of nephrotic
syndrome is itself exacerbated by concomitant liver disease. Hypotension can be present not
only because of a “low-output” state, but also because of associated autonomic neuropathy.
Involvement of the heart is the commonest cause of death in AL amyloidosis, and a
major determinant of prognosis; without cardiac involvement, AL amyloidosis has a median
survival of around 4 years32 but the prognosis among affected patients with markedly
elevated BNP and cardiac troponin (Mayo stage III disease)33 is in the order of 6-8 months.
6.3.2 Hereditary Amyloidoses:
Mutations in a number of genes, such as TTR, fibrinogen, apolipoprotein A1 and A2 can
be responsible for hereditary amyloidosis but by far the most common cause is variant ATTR
amyloidosis, caused by point mutations in the TTR gene leading to neuropathy and often,
cardiac involvement.
TTR is synthesised in the liver and a number of point mutations are described (see
table 1) but the most common is the Val122Ile mutation.34, 35 In a large autopsy study that
included individuals with cardiac amyloidosis, the TTR Val122Ile allele was present in 3.9% of
all African Americans and 23% of African Americans with cardiac amyloidosis. Penetrance of
the mutation is not truly known and is associated with a late-onset cardiomyopathy that is
indistinguishable from SSA. Although the prevalence of disease caused by this mutation is
unknown, recent evidence suggests it is almost certainly underdiagnosed,36 since the wall
thickening is often incorrectly attributed to hypertensive heart disease. The male to female
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ratio is around 50:50, in contrast to a slight male predilection in AL amyloid with cardiac
involvement.23
Over 100 genetic variants of TTR are associated with amyloidosis. Most present as
the clinical syndrome of progressive peripheral and autonomic neuropathy. Unlike wild type
ATTR or variant ATTR Val122Ile, the features of other variant ATTR include, vitreous amyloid
deposits or rarely deposits in other organs. Cardiac involvement in variant ATTR varies by
mutations and can be the presenting, or indeed the only clinical feature.37 For example,
cardiac involvement is rare in variant ATTR associated with Val30Met (a common variant in
Portugal or Sweden), but is almost universal and develops early in individuals with variant
ATTR due to Thr60Ala mutation (a mutation common in Ireland).
Mutations in apolipoprotein A1 gene can cause systemic amyloidosis, typically causing
renal and hepatic involvement - although cardiac involvement is well recognised.38
6.3.3 Senile Systemic Amyloidosis:
Wild type TTR amyloid deposits are found at autopsy in about 25% of individuals older
than 80 years, but their clinical significance has not been clear39-41 The epidemiological studies
assessing the prevalence of wild type TTR deposits, leading to the clinical syndrome of wild
type ATTR cardiac amyloidosis, remains to be ascertained but is distinct and clearly far rarer.
Wild Type ATTR is a predominant cardiac disease and the only other significant extracardiac
feature is a history of carpal tunnel syndrome, often preceding heart failure by 3-5 years.42, 43
Extracardiac involvement is most unusual.
Both wild type ATTR as well as ATTR due to Val122Ile are diseases of the over 60 year
old age group and are often misdiagnosed as hypertensive heart disease.14 Wild Type ATTR
has a strong male predominance and the natural history remains poorly understood, but
studies suggest a median survival of about 6-7 years from presentation.39, 40 The true
incidence of wild type ATTR is probably underestimated36 and recent developments in CMR,
which have greatly improved detection of cardiac amyloid during life, suggest that wild type
ATTR is more common than previously thought – it accounted for 0.5% of all patients seen at
the UK amyloidosis centre until 2001 but now accounts of 7% of 1100 cases with amyloidosis
seen since end of 2009.44 This observation is also in part explained by the ageing population.
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There appears to be an association between wild type ATTR and history of myocardial
infarction (MI), G/G (Val/Val) exon 24 polymorphism in the alpha2-macroglobulin (alpha2M),
and the H2 haplotype of the tau gene;45 the association of tau with Alzheimer’s disease raises
interesting questions as both are amyloid-associated diseases of ageing. Whilst the
echocardiographic manifestations of cardiac ATTR may be indistinguishable from advanced AL
amyloidosis, patients with the former typically have fewer symptoms and better survival.46
6.3.4 Other types of cardiac amyloidosis:
Localised atrial amyloid deposits derived from atrial natriuretic peptide (ANP), are
associated with AF, notably post operatively14, 47 and become ubiquitous with age, being
present at autopsy in 80% of over 70s.48, 49 The significance and causality of ANP amyloid
deposits remain unknown. Amyloid of as yet unknown fibril type is also common in explanted
cardiac valves.50, 51 Systemic AA amyloidosis complicating chronic inflammatory diseases, in
which the amyloid fibrils are derived from the acute-phase reactant, serum amyloid A (SAA)
protein, involves the heart in about 2% of cases with systemic AA amyloidosis. Incidence of
AA amyloidosis is generally in decline, likely reflecting better treatment for rheumatological
disorders with biological agents.
6.4 DIAGNOSIS AND EVALUATION OF CARDIAC AMYLOIDOSIS:
6.4.1 Electrocardiography (ECG):
Low QRS voltages (all limb leads <5 mm in height) with poor R wave progression in the
chest leads (pseudoinfarction pattern) occur in up to 50% of patients with cardiac AL
amyloidosis.52 The combination of low ECG voltage with concentrically increased wall
thickness is highly suspicious for cardiac amyloidosis (see figure 2), but voltage criteria for left
ventricular hypertrophy (LVH) can nevertheless sometimes occur.5354
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Figure 2: ECG of a patient with Cardiac AL Amyloidosis showing small QRS voltages (defined as ≤6mm height), predominantly in the limb leads and pseudoinfarction pattern in the anterior leads.
A recent, small evaluation of ECGs in cardiac AL amyloidosis52 supported the findings of
the largest reported ECG series of 127 patients with AL amyloidosis and biopsy-proven cardiac
involvement seen at the Mayo Clinic. The 2 most common abnormalities were low voltage
(particularly in the limb leads) and a pseudoinfarction pattern, which were seen in 45-50% of
cases. The mechanisms, however, are poorly understood.
Other findings include first degree atrioventricular (AV) block (21%), nonspecific
intraventricular conduction delay (16%), second or third degree AV block (3%), AF/flutter
(20%), and ventricular tachycardia (VT) (5%).53 Left (LBBB) and right bundle branch block can
also occur.23 ECG patterns can provide clues to differentiate between AL and ATTR
amyloidosis: LBBB is seen in 40% of patients with wild type ATTR but is rare in AL (4%), while
typical low QRS voltages are seen in 40% wild type ATTR vs 60% AL.55
There has been little recent study of ECG correlation with cardiac biomarkers,
treatment toxicity and mortality. Progressive ECG changes may be useful in assessing silent
cardiac progression.56 Changes in ECG abnormalities after treatment in AL amyloidosis remain
poorly studied, but can occur – more often, little improvement is seen. Holter ECG monitoring
identifies asymptomatic arrhythmias in >75% of cardiac AL patients (mainly supraventricular
tachyarrhythmias and some non-sustained VT).57
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6.4.2 Echocardiography:
All patients with suspected amyloidosis should undergo echocardiography. Findings
are characteristic in advanced disease, but harder to elicit earlier on, and have prognostic as
well as diagnostic significance.58-60 Typical findings include concentric LVH with right
ventricular (RV) involvement, poor biventricular long axis function with (near) normal ejection
fraction (EF)61, 62 and valvular thickening (particularly in wild type or variant ATTR).55 Diastolic
dysfunction is the earliest echocardiographic abnormality and may occur before cardiac
symptoms develop.63, 64 As with all investigations, echocardiography must be interpreted
within the clinical context; a speckled or granular myocardial appearance, although
characteristic of amyloid, is an inexact finding which is dependent on machine gain settings.
Biatrial dilatation in presence of biventricular, valvular and interatrial septal thickening 63 are
useful clues to the diagnosis.
Advanced echocardiographic techniques are beginning to reveal more about the
underlying pathology and functional abnormalities, such as the twisting and untwisting cardiac
motion that may be augmented through compensatory mechanisms before reversing to
impairment later in the course of the disease.65, 66 Strain and strain rate imaging, derived from
speckle tracking (see figure 3), may help differentiate cardiac amyloidosis from hypertrophic
cardiomyopathy.67, 68
Figure 3: Transthoracic echocardiogram with speckle tracking:. The red and yellow lines represent longitudinal motion in the basal segments while the purple and green lines represent apical motion. This shows loss of longitudinal ventricular contraction at the base compared to apex.
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Typically, there is much greater restriction of basal compared to apical movement.
Mean LV basal strain is an independent predictor of both cardiac and overall deaths. Contrast
echocardiography using transpulmonary bubble contrast can show microvascular dysfunction
in AL amyloidosis.69 Although transoesophageal echo may help detect atrial appendage
thrombus in a third of cases, of AL amyloid – translation of this into routine clinical practice for
this frail and unwell patient population needs further study.63, 70
6.4.3 Cardiac Biomarkers
Measurements of BNP, its more stable N-terminal fragment (NT-proBNP), and cardiac
troponins are extremely informative in AL amyloidosis, which is the only type in which they
have been systematically studied to date. Their value in ATTR amyloidosis is yet to be
determined. BNP/NT-proBNP are cleared by the kidneys (BNP also partially cleared by the
liver), confounding evaluation of patients with kidney involvement. Elevated NT-proBNP levels
in systemic AL amyloidosis are a sensitive marker of cardiac involvement, with a cut-off
>152pmol/L being associated with higher mortality (72% vs 7.6% per year).71 Abnormal NT-
proBNP is predictive of clinically significant cardiac involvement developing in future.72
BNP/NT-proBNP, in general, reflects high filling pressures, but amyloid deposits may have a
local effect – BNP granules are found in higher quantities in myocytes adjacent to amyloid
deposits.73
Increased troponin concentrations are a marker of poor prognosis74 but the
mechanism remains unclear. In a study of 261 patients with newly diagnosed AL amyloidosis,
median survival for patients with or without detectable levels of Troponin T was 6 months and
22 months, respectively.74 Indeed more recently, high-sensitivity Troponin T has been shown
to correlate with morbidity and mortality after patients with renal impairment were
excluded.75 High-sensitivity Troponin is abnormal in more than 90% of cardiac AL patients,76
and the combination of BNP/NT-proBNP plus troponin measurements are used to stage and
risk-stratify patients with AL amyloidosis at diagnosis.33, 77
Interestingly, the concentration of BNP/NT-proBNP in AL amyloidosis may fall
dramatically within weeks following chemotherapy that substantially reduces the production
of amyloidogenic light chains.78 The basis for this very rapid phenomenon, which is not
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mirrored by changes on echocardiography or CMR remains uncertain, but a substantial fall is
associated with improved outcomes.79 An early transient increase in BNP/NT-proBNP may
occur after treatment with the immunomodulatory drugs thalidomide and lenalidomide,
which are frequently used in the management of AL amyloidosis (see later), but the
significance and cause is unclear.80, 81
6.4.4 Radionuclide Imaging:
Serum amyloid P component (SAP) scintigraphy uses purified human SAP radiolabelled
with 123I, which is injected into patients. The tracer localises to target organs rich in amyloid
and an image captured with a gamma camera. SAP scans enable visceral amyloid deposits,
including those in the liver, kidneys, spleen, adrenal glands and bones to be imaged serially in
a specific and qualitative manner.82 It does not adequately image the moving heart, in part
because the high atomic mass of SAP (125kDa) prevents movement across myocardial
capillary endothelium and thus has no role in assessing cardiac amyloidosis. SAP scans are
described further and illustrated in section 6.5 “Liver and Spleen,” later in this chapter.
Numerous case reports over the past 30 years have indicated that various commonly
used diphosphonate bone seeking radionuclide tracers occasionally localise to cardiac
amyloid, and this approach has lately been investigated systematically. It transpires that
technetium-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid bone scanning agent
(99mTc-DPD), a particular tracer that has been little used of late for bone scintigraphy, appears
to localise to cardiac amyloid deposits very sensitively, especially in patients with ATTR type
(see figure 4), where it has become the gold standard imaging test for cardiac ATTR amyloid.
Indeed, asymptomatic cardiac ATTR deposits can be identified through 99mTc-DPD scintigraphy
at an early stage when echocardiography, serum cardiac biomarkers and perhaps even CMR
remain normal. 82
By contrast, uptake of 99mTc-DPD occurs in about one third of patients with cardiac AL
amyloidosis, and 99mTc-DPD-SPECT-CT can help to distinguish the two types.83 The sensitivity
of DPD scintigraphy for detecting cardiac amyloidosis of ATTR type would appear to have
considerable potential for diagnosis and screening.84 Early work using N-[methyl-(11)C]2-(4’-
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methylamino-phenyl)-6-hydroxybenzothiazole ((11)C-PIB) PET imaging for cardiac amyloidosis
is promising.85
Figure 4: A positive 99mTc-DPD scan for ATTR cardiac amyloid (left), showing uptake in the heart (arrow) and reduced bone uptake. The right hand panel showed a fused CT/SPECT image showing myocardial uptake with greater uptake in the septum.
In reality, because of the much lower sensitivity of DPD scintigraphy in AL compared
with ATTR amyloidosis, a multimodality imaging approach is adopted using radionuclide
scintigraphy as described above, along with cardiac MRI as described below.
6.4.5 Cardiac MRI:
CMR provides functional and morphological information on cardiac amyloid in a similar
way to echocardiography, though the latter is superior for evaluating and quantifying diastolic
abnormalities. An advantage of CMR is in myocardial tissue characterisation. Amyloidotic
myocardium reveals subtle (but see later with the new methods) pre-contrast abnormalities
(T1, T2)86, 87 but extravascular contrast agents based on chelated gadolinium provided key
information. The appearance (see figure 5) of global, subendocardial LGE, is highly
characteristic of cardiac amyloid88, 89 and correlates with prognosis,90, 91 although other LGE
patterns are also recognised (see figure 6). These factors are explored in more detail later in
this thesis. CMR is especially useful in patients with other causes of LVH, since it can
differentiate amyloidosis from hypertension, which may not be possible by routine
echocardiography.
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Figure 5: CMR with the classic amyloid global, subendocardial late gadolinium enhancement pattern in the left ventricle with blood and mid-/epi-myocardium nulling together.
Figure 6: LGE patterns: (A) Characteristic global, subendocardial; (B) patchy; (C) extensive and (D) LGE in a patient without hypertrophy (maximum wall thickness in this individual was 10mm)
Difficulties are however often encountered, for example arrhythmias, particularly AF
and ectopic beats, degrade image quality during CMR, and increasing experience of the
technique in clinical practice has shown that the pattern of LGE can be atypical and patchy,
especially in early disease.92 LGE imaging in amyloidosis is inherently challenging since amyloid
infiltration within the interstitium of the heart reduces the differences in contrast signal
between blood and myocardium such that the two compartments may null together or even
be reversed and effusions may cause considerable ghosting artefact, although these both can
be a strong clue to the underlying diagnosis (see figure 7).89, 93, 94
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Figure 7: Sequential static images from a CMR TI scout sequence after gadolinium administration. As the inversion time (TI) increases, myocardium nulls first (arrow in image 3), followed by blood afterwards (arrow in image 6), implying that there is more gadolinium contrast in the myocardium than blood
6.4.6 Endomyocardial biopsy:
Endomyocardial biopsy has been considered to be the gold standard for demonstrating
cardiac amyloid deposition.95 Although cardiac involvement can reasonably be inferred in a
patient with proven systemic amyloidosis through a combination of clinical features, ECG,
echocardiography and biomarkers etc., endomyocardial biopsy is required when suspected
cardiac amyloidosis is an isolated feature and/or when identification of the cardiac amyloid
fibril type cannot be defined by other means. In practice, endomyocardial biopsies are most
commonly required to differentiate between AL and ATTR in older patients, some 5% of
whom have a monoclonal gammopathy of undetermined significance (MGUS),96 and should
be considered in patients with LV thickening by echocardiography where hypertension,
valvular disease and a family history of HCM have been excluded, particularly if the patient is
young.
Complications such as perforation remain a small but real risk and may not be well
tolerated in restrictive cardiomyopathy.97, 98 The presence of amyloid deposition should be
confirmed by Congo red staining, and immunohistochemistry can usefully identify fibril type in
about 60-70% cases. Electron microscopy to confirm or refute the presence of amyloid fibrils
has an occasional role when Congo red stains fail to produce definitive results.99, 100
Proteomic typing of amyloid by mass spectrometry using tiny samples obtained through laser
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capture micro-dissection of tissue sections usually provides definitive results,101 and is critical
when immunohistochemistry has not done so.
6.5 LIVER AND SPLEEN:
The liver is affected in around 25-30% with Systemic AL Amyloidosis. It presents either
as hepatomegaly or as previously undetected liver enzyme derangement.31 Rarely, it can
present with life threatening hepatic rupture,102 which is also seen in some other hereditary,
non-TTR amyloid types.103
SAP scintigraphy is the gold standard for assessing disease burden within the liver. As
mentioned earlier, its high atomic mass of 125kDa favours evaluation of tissues with a
fenestrated endothelium, such as the liver and spleen. A qualitative assessment is made
ranging from the “congested” appearance seen in ATTR type amyloid, to the small, moderate
and large loads seen in AL and some other hereditary, non-ATTR amyloids (see figure 8).
Figure 8: SAP scans showing (A) Large amyloid load in liver and spleen in a patient with AL Amyloidosis; (B) Congested liver and spleen in a patient with TTR amyloid
Splenic amyloid is seldom of clinical significance and is most commonly involved in AA
Amyloidosis, but some cases of AL Amyloid also show uptake on SAP scintigraphy (see figure
9).
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Figure 9: SAP scan showing moderate load in the spleen and the right adrenal gland (arrow) in a patient with AA Amyloidosis
6.6 SKELETAL MUSCLE:
Skeletal muscle amyloidosis is rare and little is known about it. It has been described in
hereditary Apo A2104 and senile amyloidosis105 in mice. Primary (AL) Amyloidosis can however
also present with myopathy (e.g. dropped head syndrome)106 and there are a number of case
reports of patients with myeloma / lymphoma who have amyloid deposits in skeletal muscle
histologically, with confirmed myopathic changes on EMG.107-109 There is no good non-invasive
imaging technique to diagnose this condition. CT scanning can reveal infiltrative changes but
muscle biopsy remains the diagnostic gold standard.
6.7 PROGNOSIS:
In the absence of treatment, the natural history of AL amyloidosis is rapidly
progressive, with death occurring within 2 years in about 80% of patients;14 it is much worse
with cardiac involvement and heart failure. In a study of 18 patients with amyloid heart
involvement due to SSA, the median survival was 60 months; over the same period, patients
with AL amyloid heart disease at the same institution had a median survival of only 5.4
months.40 Despite thicker walls and an older age, the senile amyloid patients had less severe
heart failure and a much longer median survival (75 vs 11 months). Similar results have been
recently reported in a large series comparing different forms of amyloid cardiomyopathy.55
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5.8 TREATMENT:
Cardiac amyloidosis in general has a poor prognosis, but this differs according to
amyloid type, and availability and response to therapy. Treatment may be “amyloid-specific”
or “non amyloid-specific” as detailed below:
6.8.1 Non Amyloid Specific:
6.8.1.1 Heart Failure Therapy:
Standard heart failure therapy may be of limited benefit or even detrimental in cardiac
amyloidosis. There is scanty evidence for the use (or not) of ACE-i, ARBs and β-blockers.
These may be poorly tolerated, worsen postural hypotension or renal function (ACE/ARBs)
Restrictive cardiomyopathy leads to a heart-rate dependent cardiac output in some cases and
such patients may find difficulty in tolerating beta-blockers. Digitalis and calcium channel
blockers may be selectively concentrated in amyloidotic tissue and are relatively
contraindicated on grounds of increased toxicity110-112 especially the latter, which can lead to
rapid worsening. Careful monitoring is needed to avoid significant drug interactions e.g. β-
blockers with thalidomide used in chemotherapy of AL amyloidosis causing bradycardia.113
Maintenance of adequate filling pressures is vital due to the restrictive physiology;
balancing peripheral oedema and renal impairment with salt/water restriction and judicious
use of diuretics is also important. Patient education and participation, ideally with backup
from heart-failure teams, is critical to successful management. Contrary to standard heart
failure management, maintenance of adequate blood pressure with an α-agonist like
midodrine may permit higher doses of loop diuretics especially in patients with autonomic
neuropathy.114
6.8.1.2 Device therapy:
Pacemakers or implantable cardioverter-defibrillators (ICDs) may not prevent sudden
cardiac death, since this is thought to often be due to electromechanical dissociation.115 In the
absence of evidence, pacing indications remain within current standard guidelines. High
defibrillator thresholds may be encountered and the benefits of such devices remain
uncertain.115 116, 117 Biventricular pacing appears to play little role – but may be the ideal
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pacing option of choice to avoid decompensation of the stiffened ventricle as a result of
induced dyssynchrony from RV pacing. 118
6.8.1.3 Cardiac transplantation in amyloidosis:
Cardiac transplantation has played a disappointingly small role, due to the multisystem
nature of amyloidosis, advanced age, treatment related complications, and rapid disease
progression. Furthermore, patients with AL amyloidosis must be deemed likely to be
sufficiently fit to undergo chemotherapy afterwards, to address the underlying bone marrow
disorder. As a result, only a few dozen cardiac transplants have ever been performed for
amyloidosis. However, the long-term outcome can be good in highly-selected patients with
AL amyloidosis.119 Cardiac transplantation followed by successful peripheral blood autologous
stem cell transplantation (ASCT) was associated with better survival in selected patients as
reported120 from most major amyloidosis units in the UK,119 France,121 Germany122 and the
USA.123
A suitable patient with AL amyloidosis is likely to be young (<60 yrs), have isolated
Mayo stage III cardiac amyloidosis, NYHA III or IV symptoms after adequate diuretics, good
renal/liver function, no significant autonomic neuropathy, low level bone marrow plasma-
cytosis and be eligible for ASCT after the heart transplant. Even in such patients, outcomes
are probably inferior to other indications.124 For variant ATTR, combined cardiac and liver
transplantation has been performed in a few dozen cases throughout the world.119, 120, 125, 126
Although most patients with wild type ATTR are too elderly for cardiac transplantation, the
absence of extra-cardiac involvement renders younger patients with wild type ATTR excellent
candidates. The two patients with wild type ATTR who presented to the UK national
amyloidosis centre before age 60, survived 10 and 20 years respectively following cardiac
transplantation (unpublished data).
6.8.2 Amyloid Specific:
6.8.2.1 Reducing amyloid fibril precursor protein production:
Treatment of amyloidosis is currently based on the concept of reducing the supply
of the respective amyloid fibril precursor protein. In AL amyloidosis, therapy is directed
towards the clonal plasma cells using either cyclical combination chemotherapy or high dose
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therapy with ASCT. Most chemotherapy regimes in AL amyloidosis comprise dexamethasone
combined with an alkylator (oral melphalan or others).
Addition of thalidomide, for example in the risk-adapted cyclophosphamide,
thalidomide and dexamethasone (CTD) regime used widely in the UK, improves response rates
but probably at cost of greater toxicity.127 Dexamethasone, although a very useful agent in all
patients with AL amyloidosis including those with cardiac involvement, has to be used with
great caution in patients with cardiac amyloidosis due to a high risk of fluid overload in the
absence of adequate and rapid changes to diuretic therapy. Close coordination between the
treating haematology and cardiology teams is critical to steer the patient successfully through
the treatment course.128 In a study of 75 AL patients, CTD (and attenuated dose CTD)
produced a complete response (CR) in 21%. Estimated 3-year survivals for those achieving a
CR, partial response (PR), or no response were 100%, 82%, and 0%, respectively (median
survival 17 months).
High-dose melphalan followed by ASCT provides a more durable haematological
response. In the largest published series of melphalan-primed ASCT (n=701), 312 AL patients
were deemed eligible for high-dose chemotherapy, and the median survival of treated
patients was 4.6 years. A CR was achieved in 40%, although the mortality rate in the first 100
days was 13%. Survival was poorer amongst patients with cardiac amyloidosis compared to
those who had no evidence of heart involvement.129 Although it has been argued that ASCT is
the best treatment for suitable patients,130-132 its role in the era of more novel agents
(discussed below), is less certain.
The newer treatment options include bortezomib (a proteosome inhibitor)133 and
the newer immune-modulatory drugs, such as lenalidomide and pomalidomide. Bortezomib
combinations appear to be especially efficient in amyloidosis with high rates of near CRs
which appear to translate into early cardiac responses.134-136 Phase II (bortezomib in
combination with cyclophosphamide or doxorubicin) and phase III (bortezomib, melphalan
and dexamethasone compared to melphalan and dexamethasone as front line treatment)
trials are underway.
AA amyloidosis is the only other type of amyloidosis in which production of the fibril
precursor protein can be effectively suppressed by currently available therapies. Anti-
inflammatory therapies, for example anti-TNF agents in rheumatoid arthritis, can substantially
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suppress serum amyloid A protein production, but very little experience has been obtained
regarding cardiac involvement which is very rare in this particular type of amyloidosis.
ATTR is produced almost exclusively in the liver. Liver transplantation has been used as
a treatment for variant ATTR for 20 years, to remove genetically variant TTR from the plasma.
Although this is a successful approach in ATTR Val30Met, it has had disappointing results in
patients with other ATTR variants which often involve the heart. The procedure commonly
results in progressive cardiac amyloidosis through on-going accumulation of wild-type TTR on
the existing template of variant TTR amyloid.137 The role of liver transplantation in non-
Val30Met associated hereditary TTR amyloidosis thus remains very uncertain. Exercise
training post surgery can be helpful however.138
ATTR amyloidosis has lately become a focus for novel drug developments aimed at
reducing production of TTR through silencing RNA and antisense oligonucleotide therapies.
ALN-TTR01, a systemically delivered silencing RNA therapeutic139 is already in phase I clinical
trial.
6.8.2.2 Inhibition of amyloid formation:
Amyloid fibril formation involves massive conformational transformation of the
respective precursor protein into a completely different form with a predominantly β-pleated
sheet structure. The hypothesis that this conversion might be inhibited by stabilising the fibril
precursor protein through specific binding to a pharmaceutical product has lately been
explored in ATTR amyloidosis. A key step in TTR amyloid fibril formation is the dissociation of
the normal TTR tetramer into a monomeric species that can auto-aggregate into a misfolded
form. In vitro studies identified that diflunisal, a now little used non-steroidal anti-
inflammatory analgesic, is bound by TTR in plasma, and that this enhances the stability of the
normal soluble structure of the protein.140, 141 Studies of diflunisal in ATTR are in progress.
Tafamidis is a new compound without anti-inflammatory analgesic properties that has
a similar mechanism of action. Tafamidis has just been licensed for neuropathic ATTR but its
role in cardiac amyloidosis remains uncertain – clinical trial results are eagerly awaited.
Higher affinity ‘superstabilizers’ are also in development.142
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Eprodisate is a negatively-charged, sulphonated molecule with similarities to heparin
sulphate, which is being pursued as a treatment for AA amyloidosis. Eprodisate is thought to
inhibit the pro-amyloidogenic interactions of GAGS with SAA during fibril formation in AA
amyloidosis. A phase III trial showed benefits in terms of progression of AA amyloid
associated renal dysfunction143 and further studies are currently being conducted.
6.8.2.3 Targeting Amyloid Deposits by Immunotherapy:
Amyloid deposits are remarkably stable, but the body evidently has some limited
capacity to remove them. Following treatment that prevents the production of new amyloid,
e.g. successful chemotherapy in AL type, amyloid deposits are gradually mobilised in the
majority of patients, though at different rates in different organs and between individuals.
Unfortunately clearance of amyloid is especially slow in the heart, and echocardiographic
evidence of improvement is rare, even over several years.
The challenge of developing a therapeutic monoclonal antibody that is reactive with all
types of amyloidosis is currently being addressed by targeting SAP, since this is a universal
constituent of all amyloid deposits and an excellent immunogen. Anti-SAP antibody treatment
is clinically feasible because circulating human SAP can be depleted in patients by the bis-d-
proline compound CPHPC, thereby enabling injected anti-SAP antibodies to reach residual SAP
in the amyloid deposits (see figure 10 on the next page).3 The unprecedented capacity of this
novel combined therapy to eliminate amyloid deposits in mice is encouraging and should be
applicable to all forms of human systemic and local amyloidosis; trials are currently underway.
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Figure 10: Showing (A) cross-linking of SAP by the R-1-[6-[R-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl] pyrrolidine-2-carboxylic acid (CPHPC) molecule; (B) Circulating SAP in a patient with amyloidosis, showing the normal level of “coating” of amyloidotic organs by SAP and baseline low-level sequestration of circulating SAP by the liver; (C) Addition of CPHPC causing cross-linking of SAP in the blood and subsequent high level excretion of SAP from blood by the liver; (D) Addition of the anti-SAP antibody causing removal of SAP coating from amyloidotic organs, allowing immune system to destroy the amyloid in the target organ. Picture courtesy of Duncan Richards, GSK.
6.9 MEASURING INTERSTITIAL EXPANSION USING MRI:
6.9.1 MRI General Physics:
The majority of protons in the body align in the direction of the magnetic field B0 when
placed in the MRI scanner, as this is the lower energy state. A radiofrequency (RF) impulse at
the Larmor frequency induces a higher energy state within the proton, causing it to spiral
away from the B0 alignment to an angle (flip angle) proportionate to the RF pulse. When the
RF pulse stops, the proton slowly relaxes and energy is dissipated to the surrounding nuclei;
this corresponds with the return of longitudinal magnetisation to the original B0 alignment as
calculated by 1 – e-t/T1. The time constant of this exponential is known as the T1 relaxation
time and represents the time taken for 63% of longitudinal magnetisation to recover after the
RF impulse (see figure 11)
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Figure 11: Magnetisation recovery curve plotted against time demonstrating T1 for myocardium.
T1 is therefore dependent on magnetic field strength. All tissues have an intrinsic T1
which is a composite signal representing cells and the interstitium. Any change in cell size or
number will alter the T1. Similarly, any change in the interstitium such as scarring from MI or
infiltration by amyloid will also change the T1 from normal. In general, the higher the water
content, the higher the T1. The T1 of normal myocardium is approximately 960 ± 30ms. A high
or low myocardial T1 can therefore give tissue characterisation and allow some inference as to
the cause of the abnormal areas of myocardium in question. For example, the T1 varies widely
from as low as 300-400ms in iron-loaded hearts to almost 2000ms in oedematous
myocardium as seen in myocarditis.
T1 can be significantly lowered by administration of Gadolinium. There are many
preparations, though cyclic, ionic compounds such as Gadoterate Meglumine (Dotarem) are
thought to be the safest in terms of the lowest risk of nephrogenic systemic fibrosis.
Gadolinium is a purely extracellular agent and produces a local environment in the
interstitium that allows protons to relax by a factor of x106 faster than normal. In areas of
gross interstitial expansion due to amyloid, gadolinium concentration is proportionately
higher in these areas and causes the T1 in these areas to drop lower than compared to the
surrounding or adjacent (normal) tissue (see figure 12), thus producing the contrast between
black and white in the late gadolinium enhancement pictures shown in figures 6 and 7 earlier.
This property of gadolinium is also the crux of the Equilibrium-CMR technique described
shortly in section 6.10.
0 1 2 3 4 5
Time (s)
Lo
ng
itu
din
al
Mag
neti
zati
on
(M
z)
Myocardium
63% Myocardium
T1=1000ms
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Figure 12: Graph showing change in concentration of gadolinium with time after IV bolus. Blue line shows concentrations in the interstitium of normal myocardium and the red line in abnormal (infarcted) myocardium. The difference in concentration at 10-20 mins (marked “contrast”) creates the standard LGE image with normal myocardium black and scar appearing as white. Picture courtesy of Dr. Daniel Sado, The Heart Hospital.
6.9.2 T1 Mapping:
A number of techniques are currently in widespread use in the CMR community to
measure T1 values of tissues. The earliest method was using a Look Locker (TI scout) sequence
prior to the administration of gadolinium contrast (see figure 13), which took multiple images
throughout several cardiac cycles after an RF pulse. From these, a region of interest (ROI)
could be drawn and the signal intensities plotted against time on a recovery curve similar to
figure 11 to determine the T1. This method had the disadvantage that it required a long
breath hold from patients and also images were not acquired at the same point in the cardiac
cycle.
Figure 13: A pre contrast TI scout image showing the different signal intensities of the myocardium at increasing time points (100ms to 3882ms) after a RF impulse.
Page 44 of 150
In 2004, the modified Look Locker T1 mapping (MOLLI)144 sequence was developed.
This sends out an RF impulse and reads out at 3 time-points along the T1 recovery curve. A
further 2 RF impulses are applied to the selected tissue and read outs (3 and 5 respectively)
along the recovery are taken after each RF impulse. Three recovery curves are then available
to determine the tissue T1. The result is a pixel by pixel T1 map displayed as a graded colour
image according to the T1 of each pixel. This is summarised in the schematic in figure 14.
MOLLI had the advantage of being more accurate than the Look Locker sequence
because it samples at the sampled at the same point in the cardiac cycle. But the breath hold
is very long for most patients (around 20 seconds in some instances) and as such, is also more
susceptible to heart rate changes and ectopics.
Figure 14: Schematic showing 3 RF impulses (boxes) and their subsequent readouts plotted on the recovery curve, coloured in green, red and blue respectively. This produces the colour, pixel by pixel T1 map. Courtesy of Dr. Stefan Piechnik, OCMR Unit, Oxford.
Later in 2010, in order to make the MOLLI more clinically applicable, it was shortened
to become the ShMOLLI.145 Certain assumptions needed to be made to achieve this, for
example that the recovery periods after each RF impulse need not be as long as the MOLLI
such that at heart rates with an R-R interval of approximately 1000msec, even though 3 RF
impulses were applied, only 1 recovery curve of 5 plots was required to determine the T1 of
the myocardium; however, if the heart rate was particularly fast or the T1 of the tissue in
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question was particularly low, information from the 2nd and 3rd recovery curves was then
taken into consideration. The data obtained from the ShMOLLI experiment then undergoes
automated mathematical correction and curve fitting performed by the Siemens computer
which is used to control the scanner. This is used to calculate the T1 of each image pixel in the
slice selected, which is then assigned a colour according to its value as shown below in figure
15.
Figure 15: Pre-contrast ShMOLLI image showing (A) Normal myocardium appearing green, and (B) Amyloid myocardium appearing thickened with areas of red (high T1 signal) appearing in the otherwise green myocardium.
These assumptions meant the T1 map could now be taken in around 9 seconds. The
ShMOLLI was also found to be more heart rate independent and T1 independent than the
MOLLI as a result. Therefore, the pre-contrast T1 work presented in this thesis uses this
ShMOLLI technique.
More recently, the MOLLI has been motion corrected to improve accuracy and newer
techniques such as the saturation recovery, single-shot acquisition (SASHA) are entering the
field,146 but these are not considered in this thesis.
6.10 EQUILIBRIUM CMR (EQ-CMR):
Prior to the advent of ShMOLLI, our group in 2009 devised the first method of non-
invasively quantifying in the interstitium of the heart using the technique of EQ-CMR.147 There
are 3 principles underlying this technique: (1) Gadolinium infusion to achieve equilibrium; (2)
T1 measurement before and after gadolinium; (3) Haematocrit result.
Because of some of the limitations of T1 mapping at that time, it was felt that the most
accurate method was T1 measurement using multiple, high resolution, fast, low-angle shot
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(FLASH) inversion recovery images of a single, piloted view (usually the 4-chamber view) at
specific inversion times (TI) ranging from 200ms to 100ms. This was done first of all prior to
any gadolinium administration and gave the highest resolution images for ROIs to be drawn in
the heart and blood pool to obtain the mean signal intensity at each TI, as shown in figure 16
below:
Figure 16: FLASH T1 measurement method for the heart. A 4-chamber slice is shown at different TIs with ROIs (blue) drawn in aorta and basal septum.
Mean tissue signal intensities were then plotted against TI. The TI producing the lowest
signal intensity was identified and the magnitude of the signal intensities plotted to the left of
this point were made negative. This allowed reconstruction of the full range of the T1 signal
intensity inversion recovery curve. A second-order polynomial curve-fitting technique was
used to find the null point (see figure 17). A previously validated algorithm was then used to
correct for incomplete longitudinal recovery giving a corrected T1.
Figure 17: Graph showing signal intensity plotted against inversion time using a second-order, polynomial curve fitting technique to determine the null point and thus the T1 for myocardium.
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Gadolinium was then administered as an intravenous bolus at a dose of 0.1mmol/kg,
followed by a primed infusion of gadolinium at a rate of 0.0011mmol/kg/min. The infusion is
necessary to create true equilibrium and eliminate the effect of gadolinium kinetics on the
measured T1. If the infusion was not given, the T1 of both blood and myocardium would
simply drop precipitously after the bolus injection of gadolinium before slowly returning to
normal over the course of an hour or so (see figure 18A). Any T1 measurement in this
situation would be affected by dynamic movement of gadolinium between extravascular
compartments of blood and myocardium. Additionally, wash in and wash out is slower in
abnormal myocardium compared to normal myocardium, and there is also the issue of renal
excretion; hence, an infusion is required to achieve true equilibrium between blood and
myocardium and thus eliminate any interference in T1 results from gadolinium kinetics (see
figure 18B).
Figure 18: Graph showing change in inversion time for myocardium and blood, with time after an IV gadolinium bolus (time 0) and - (A) No infusion, allowing TI to return to normal over 1 hour and (B) Primed gadolinium infusion commencing at T = 15 minutes holding TI stable over the course of the infusion. Image courtesy of Dr. Andrew Flett.
Thirty minutes after the gadolinium infusion, equilibrium is reached. The T1
measurements are again taken in the manner described above. At this stage, the
concentration of gadolinium in the interstitium of myocardium and plasma is the same. And as
the rate of change of T1 (∆T1) is proportional to the concentration of gadolinium in the
extracellular space (or volume i.e. ECV), then the following equation is true:
ECV = λ (1-haematocrit)
where λ =
and R1 =
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The end result is several signal intensity readings for myocardium and blood, before
and after contrast, at multiple inversion times. These can be plotted on graphs as shown in
figure 17 earlier, so that the rate of change of T1 for myocardium and blood can be calculated
(see figure 19 below) and subsequently the ECV calculated.
Figure 19: Graph showing typical changes in signal intensity plotted against inversion time for myocardium (blue) and blood (red), both pre- and post-contrast. Image courtesy of Dr. Andrew Flett.
Proof of principle was first demonstrated in 25 patients with severe aortic stenosis (AS)
undergoing aortic valve replacement (AVR). The ECV was calculated using EQ-CMR and the
results compared to histology from a septal biopsy performed during the AVR. There was a
strong correlation of ECV with collagen volume fraction (R2 0.80, P<0.001), suggesting ECV as
assessed by EQ-CMR was quantifying diffuse fibrosis in the interstitium accurately (see figure
20 on the next page).147
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Figure 20: Scatter graph showing linear association of myocardial ECV with collagen volume fraction in aortic stenosis. Figure courtesy of Dr. Andrew Flett published in Circulation, 2010.147
ECV was then assessed in a host of other cardiomyopathies and compared to normals.
HCM (n=31), MI (n=20), familial dilated cardiomyopathy (DCM, n=31), severe AS (n=66) and
Anderson Fabry’s disease (AFD, n=17) were compared to 81 healthy volunteers. Mean ECV
was statistically significantly higher in HCM (0.29), DCM (0.28) and AS (0.27) compared to
healthy volunteers (0.25), P<0.001. AFD did not show any rise in ECV as it is a predominantly
intracellular disease process. Although there is overlap in these “low-ECV” diseases, the ECV
of the infarct zone of an MI was massively raised at 0.59 compared to normals (P<0.001) in
keeping with net rise in extracellular space due to myocyte necrosis and scar formation (see
figure 21).
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Figure 21: Graph showing relationship between myocardial ECV and various cardiac diseases as well as normal subjects. Figure courtesy of Dr. Daniel Sado published in Heart, 2012.148
The work above in EQ-CMR led to the hypothesis that: as Amyloidosis is the exemplar
of an interstitial disease process and as ECV is a purely extracellular measure, the 2 could be
combined to produce a powerful tool to not only quantify cardiac amyloid burden more
accurately, but also become a marker for treatment response and even prognosis. Current
methods of assessment of cardiac amyloid burden are reliant on surrogate markers of the
interstitial expansion rather than a true measure of it.
Wall thickness measured by echocardiography is non-specific due to other (more
common) causes of LVH. Low voltage ECGs, as mentioned earlier, is not very sensitive and
other pathologies e.g. pericardial effusions confound. Serum cardiac biomarkers such as NT-
proBNP and Troponin T are not specific to amyloid and are also affected by renal impairment
(a common mode of presentation in AL Amyloid) and chemotherapy. Cardiac biopsy is invasive
and radioisotope scanning is either not useful in AL Amyloid (DPD scan) or simply does not
image the heart at all (SAP scan).
Considering the poor prognosis carried by cardiac AL amyloidosis, any method of
accurately and non-invasively quantifying the interstitial expansion seen in cardiac
amyloidosis, detecting the disease earlier, detecting amyloid regression in cases that improve
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and predicting survival optimally in order to reduce treatment-related mortality as well
mortality due to the disease, is most welcome for these patients.
We hypothesise that T1 mapping and ECV measurement are able to achieve these
outcomes and these hypotheses are now explored further in this thesis.
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7. METHODS
7.1 ETHICAL APPROVAL:
Prior to this thesis, Dr. Andrew Flett had obtained ethical approval (ref 07/H0715/101)
to study the EQ-CMR technique in patients with AS and HCM from the joint UCL/UCLH
committee on ethics of human research. Dr. Daniel Sado then obtained 2 substantial
amendments to this which granted permission to recruit and scan healthy volunteers (n=100)
and patients with cardiac diseases (n unlimited) discussed in this thesis.
I was jointly appointed across the Heart Hospital and the National Amyloidosis Centre
(NAC). I obtained 3 minor amendments to enable contact of patients by phone for
recruitment because of the unavoidable necessity to coincide CMR scans with patients’
existing appointments with the NAC, as many of them come from lengthy distances across the
UK and Europe. The 2nd minor amendment was to create a second Patient information leaflet,
changing it from the general subject of diffuse fibrosis in HCM, DCM and AS to interstitial
expansion due to amyloid infiltration. The final amendment was to allow ethics to cover the
National Amyloidosis Centre.
I subsequently helped with the requirements of setting up CMR as an endpoint for the
first in man GSK study using my methods as a primary endpoint.
7.2 PATIENTS:
A total of 179 patients were scanned from the NAC over the course of 2010-2013.
These patients were usually attending the NAC for a 24 hour period in order to have ECG,
echo, SAP scan and a clinical consultation. All CMR scans were performed at the Heart
Hospital and it was therefore necessary to transport patients from the NAC to the Heart
Hospital and back in between their other numerous investigations. This was a limitation of the
recruitment process.
Of these 179 patients, 26 were follow up scans (2nd scans) and 6 were interstudy
reproducibility scans. The remaining 147 scans were of consecutive patients, either with a
known diagnosis of amyloidosis (i.e. follow up patients) or an unknown diagnosis (i.e. new
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referrals), attending the NAC between 2010-2013 with clinical indications for CMR and no
contraindications to either MRI or gadolinium. Patients in AF on attending the NAC were also
excluded.
Of these 147, 8 patients did not have EQ-CMR scans for the following reasons:
eGFR <30ml/min (scan done on clinical grounds with patient’s consent to gadolinium)
(n=2)
Poor pre-contrast T1 map (FLASH only patients) (n=2)
Severely orthopnoeic (n=2)
Patient refusal (n=1)
Side effects (nausea & vomiting) on gadolinium infusion, therefore infusion terminated
(n=1)
This left 139 patients who had full EQ-CMR; these are categorised as follows:
AL 100
ATTR 19
AA 3
Other hereditary 4
Localised 2
No amyloid 11
All patients had, as part of their routine clinical work up, tissue biopsy proof of amyloid
except 2 patients in the AL cohort – 1 who died before a biopsy could be obtained and the
other had a normal soft tissue biopsy but with a diagnostic SAP scan showing bone marrow
uptake. Histology was performed with Congo red followed by immunohistochemical staining,
these results are shown later in this thesis.
Before having their CMR scan, all patients were subgrouped into their pre-test
probability of having cardiac involvement as follows:149
Definite cardiac involvement – any of:
Left ventricular wall thickness of ≥12mm by echocardiography in the absence of any other
known cause
RV free wall thickening co-existing with LV thickening by echocardiography in the absence
of systemic or pulmonary hypertension
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Possible cardiac involvement – any of:
LV wall thickening by echocardiography in the presence of hypertension
RV thickening by echocardiography in the presence of pulmonary hypertension
Normal wall thickness by echocardiography with diastolic dysfunction and raised serum
biomarkers33
No suspected involvement
Normal wall thickness by echocardiography with normal serum biomarkers
The majority of chapters in this thesis refer solely to the AL Amyloid cohort. Some chapters
(e.g. reproducibility, pilot EQ-CMR in ATTR amyloidosis) also include the ATTR cohort.
7.3 HEALTHY VOLUNTEERS:
Over the course of the 2 year period, healthy volunteers (n=82) were recruited through
advertising in hospital, University and general practitioner surgeries. All had no history or
symptoms of cardiovascular disease or diabetes and were asked to fill in a health
questionnaire on arrival for their CMR scan. No patient was on cardio-active medication
except 4 on statins for primary prevention. These scans were performed and reported by Dr.
Daniel Sado and Dr. Viviana Maestrini as a comparator group for ECV studies within our group.
Some were scanned before we had the ShMOLLI sequence available to us and
therefore only 54 of the 82 healthy volunteers were scanned using the ShMOLLI T1 mapping
sequence.
7.4 CMR:
All scans were performed on a 1.5 Tesla Siemens™ Avanto scanner and images always
acquired during breath-hold at end expiration.
7.4.1 Pilot Images:
All studies started with single shot pilot images with the following settings: repeat time
(TR): 3.39ms, echo time (TE): 1.7ms, slice thickness, 5mm, field of view (FOV) 360 x 360mm,
read matrix 256 and flip angle 60o.
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7.4.2 Cine Images:
After piloting, steady state free precession (SSFP) cine imaging was then undertaken,
firstly in the long axis planes with a short axis cut through the aortic valve. A standard LV short
axis stack was then acquired using a slice thickness of 7mm with a gap of 3mm. Retrospective
ECG gating was used with 25 phases. Typical fast imaging with steady state precession (FISP)
imaging parameters were TE: 1.6ms, TR: 3.2 ms, in plane pixel size 2.3 x 1.4mm, slice thickness
7mm, flip angle 60. These settings were optimised accordingly if the subject was unable to
breath-hold, or had an arrhythmia etc..
7.4.3 Pre Contrast T1 Assessment:
7.4.3.1 FLASH Heart:
Next, pre-contrast T1 assessment for the heart was performed using the method
described in section 6.10 which is a multi–breath-hold, spoiled gradient echo, FLASH inversion
recovery sequence with the following parameters: slice thickness 8mm, flip angle=21°, FOV
400x260mm and a TR and TE set according to the heart rate to avoid misgating. Images were
taken at increasing TIs of 140 ms, then 200 to 1000 ms in 100ms increments subsequently
corrected for heart rate.
A pre-saturation band was placed across the cerebrospinal fluid (CSF) to avoid ghosting
onto the ventricular septum in the 4-chamber view, allowing a clean ROI to be drawn on the
septum. All ROIs were drawn in the 4-chamber view as shown in figure 16 (on page 46) taking
care to avoid the extremities of the blood:endocardial boundary. The signal intensity at each
TI is then plotted on a pre-designed MS Excel® graph and the T1 calculated, as described in
section 6.10.
For intrastudy reproducibility, scans were firstly analysed by myself before being
anonymised and randomised by Dr. Viviana Maestrini and then subsequently re-analysed by
myself within 24 hours; ECV results were collected by Dr. Maestrini. For interobserver
reproducibility, scans analysed and reported by myself were anonymised; the second reporter
was Dr. Maestrini and ECV results were collated by me within 7 days. For interstudy
reproducibility, scans were performed no more than 14 days apart. These scans were
anonymised and both reported by myself with ECV results collated by Dr. Maestrini.
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7.4.3.2 FLASH Liver, Spleen and Skeletal Muscle:
For the liver, spleen and skeletal muscle, axial, sagittal and coronal plane localisers
were used to plan an axial slice through the upper abdomen to include the greatest area of
liver and spleen. Pre-contrast FLASH images were acquired at this location (as for the heart)
for T1 measurement with inversion times increasing from 140 to 200ms and then to 1000ms
in 100ms increments.
In the liver, a single, large, peripherally-based, wedge-shaped polygonal ROI was drawn
in liver segment 6 and 7 so as to include the maximum area of liver tissue, but avoid visible
hepatic and portal veins. These were non-gated acquisitions with a standard TR of 2000msec
every time. A single image is shown as an example in figure 22.
Elliptical ROIs were also drawn in the spleen and paravertebral muscle to include the
maximum area of tissue and avoid adjacent vessels and fat. A circular ROI was drawn in the
abdominal aorta so as to include the greatest area of lumen, but not include aortic wall –
frequently thickened by atheroma (see figure 22).
Figure 22: Pre contrast axial MR image (inversion time, 800 msec) shows sample ROIs drawn within the abdominal aorta, spleen, liver, and paravertebral muscle.
The 4 ROIs were then copied to the EQ phase FLASH images and mean signal intensity
within each tissue at each TI recorded before being plotted on the MS Excel® graph as
described above in section 6.10. Interstudy variability was tested for the liver and spleen as
described on page 55 using Pearson’s correlation coefficient and Bland-Altman analysis.
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7.4.3.3 ShMOLLI Heart, Liver and Spleen:
In some AL amyloid patients (n=73) and healthy volunteers (n=54), ShMOLLI T1
mapping of the heart, liver and spleen were also performed in addition to FLASH T1
measurement. For the ShMOLLI mapping, typical setting were: FOV 340 x 340mm, FOV phase
69.8%, flip angle 35o, TR 1095msec, TE 1.05msec, slice thickness 8mm, 107 phase encoding
steps, interpolated voxel size=0.9x0.9x8mm, base resolution 193 and phase resolution 100.
Acquisition time was 206msec for a single image with a cardiac (trigger) delay time (TD) of
500ms; where necessary, to avoid misgating, the TD was decreased by 100ms for every 10
beats per minute above a resting heart rate of 80 beats per minute.
A ROI was then drawn in the basal septum on the 4-chamber view of the resulting
parametric T1 map, 2 pixels away from the apparent blood:endocardial boundary and were
drawn without reference to the LGE images.150 This produced the T1 value which could then
be converted to the ECV using the same equation described earlier in section 6.10.
7.4.4 LGE:
Intravenous Gadoterate meglumine (gadolinium-DOTA, marketed as Dotarem®
Guerbet, S.A., France) was then administered as a 0.1mmol/kg dose via a pressure injector at
a rate of 3ml/sec, with a 25ml normal saline flush. LGE assessment was then undertaken using
a FLASH IR sequence with slice thickness 8 mm, TR: 9.8 ms, TE: 4.6ms, α: 21o, FOV 340 x 220
mm (transverse plane), sampled matrix size 256 x 115-135, 21 k–space lines acquired every
other RR interval (21 segments with linear reordered phase encoding), spatial resolution 1.3 x
2.1 x 8 mm, no parallel imaging, pre-saturation bands over CSF and any pleural effusions.
These parameters were optimised according to individual patient characteristics. The
TI was manually set to achieve nulling of the myocardium between 300 and 440 ms. When
LGE was observed, images were acquired in phase swap and cross cut to ensure artefact
elimination. Where the LGE distribution appeared particularly diffuse, a TI scout was used to
ascertain the specific parts of myocardium with the highest concentration of gadolinium. If
the participant was struggling with the breath-hold, FISP imaging or IR-SSFP imaging (single
shot or segmented) was used as an alternative sequence.
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7.4.5 Post contrast T1 evaluation:
In some studies, 15 minutes after the bolus was given, ShMOLLI T1 mapping was
repeated, from which ECVb was derived. In all studies, an infusion of gadolinium was then
commenced at a rate of 0.0011mmol/kg/min. At this point, the participant was usually taken
out of the scanner while the infusion ran over the next 30 minutes. They were then returned
to the scanner with the infusion continuing to run. Repeat T1 assessment was performed
using the FLASH IR sequence and in most cases, the ShMOLLI T1 mapping sequence as well,
from which ECVi was derived. Post contrast ShMOLLI required off-line post-processing before
the T1 could be calculated.
7.4.6 Off line clinical analysis:
For LV volume and mass analysis, a thresholding technique was used. All of the
amyloid patients in this thesis were analysed by myself; the healthy volunteers were analysed
by Dr. Daniel Sado and Dr. Viviana Maestrini.
The healthy volunteer scans were reported by Dr. Daniel Sado and Dr. Viviana
Maestrini, with authorisation by Dr. James Moon (primary supervisor to both); all patient
studies were reported by myself and Dr. James Moon (primary supervisor and Reader in
Cardiology) using international guidelines as the basis for all reporting.151
7.5 BLOOD PRESSURE AND 12 LEAD ECG:
All patients had their blood pressure (BP) measured at the National Amyloidosis Centre
on a CareScape™ V100 machine by the nursing staff as part of their routine workup. In the
healthy volunteer cohort, BP was measured after their CMR scan by Dr. Daniel Sado and Dr.
Viviana Maestrini using a Mindray™ machine.
A 12 lead ECG was performed on all patients at the National Amyloidosis Centre on the
same day as the CMR scan, as part of their clinical work up. The ECG was acquired using a
calibration of 10 mm/mV and speed of 25 mm/s. Interpretation of the trace was performed by
myself. Healthy volunteers followed an identical protocol.
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7.6 BLOOD TESTS:
All participants had blood tests taken prior to the CMR scan at the National
Amyloidosis Centre as part of their clinical workup. This included NT-proBNP and serum free
light chain in all cases, with Troponin T in just over half the cases as this is only routinely
performed on new patients.
7.7 SIX MINUTE WALKING TEST (6MWT):
This was performed at the Heart Hospital along a flat corridor in accordance with
current guidelines.152 Patients were asked to walk a 30-metre length of the corridor at their
own pace while attempting to cover as much ground as possible in the 6-minute period.
Verbal encouragement was given using either of 2 standardised phrases: ‘‘You’re doing well’’
or ‘‘Keep up the good walk.’’ At the end of 6 minutes, participants were asked to stop and the
distance covered was recorded. Any symptoms were recorded, as was the Borg score (on a
scale of 1-10) to assess the degree of breathlessness.153
7.8 ECHOCARDIOGRAPHY:
In all patients, transthoracic echocardiography was performed at the National
Amyloidosis Centre on a Philips® IE33 machine as a part of the routine clinical work up. Echo
studies, included tissue doppler just above the mitral valve annulus at the septal and left
ventricular lateral wall. Scans were performed and analysed by 2 echocardiographers
experienced in scanning patients with cardiac amyloidosis. Accepted markers of diastolic
dysfunction i.e. isovolumic relaxation time (IVRT), E-deceleration time and E:E’ ratio were all
measured.154 Echocardiography was not used to assess left ventricular systolic function for
this work, as CMR was seen as the gold standard in this regard.151
7.9 SAP SCINTIGRAPHY:
All AL amyloid patients underwent SAP scintigraphy at the National Amyloidosis Centre
as part of their routine workup. A weight adjusted dose of purified human SAP component,
radiolabelled with 200MBq of 123I is injected into the patient. Anterior and posterior whole
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body, planar images are captured on a General Electric (GE)® Infinia gamma camera no less
than 6 hours after the injection. Total amyloid load in the liver and spleen were graded by
Prof. Philip Hawkins, who has the most experience in reporting these scans in the UK, having
co-invented the scan with Prof. Sir Mark Pepys in 1988. Grading criteria were as follows:
None – No tracer uptake into organs. Normal blood pool signal.
Small – Tracer uptake into organs with blood pool still clearly visible
Moderate – Tracer uptake into organs with blood pool only just visible
Large – Tracer uptake into organs with no blood pool visible
7.10 DPD SCINTIGRAPHY:
Most of the ATTR patients had DPD scans (instead of SAP scans) by the time of their
appointment though this was not always possible because of time and scanner limitations on
the day. Where performed, patients were scanned using a GE® Medical Systems hybrid SPECT-
CT gamma camera (Infinia Hawkeye 4) following administration of 700MBq of intravenously
injected 99mTc-DPD. Three hour (delayed) whole body planar images were acquired followed
by a single photon emission computed tomography (SPECT) of the heart with a low-dose, non-
contrast CT scan.
Gated/non-gated cardiac SPECT reconstruction and SPECT-CT image fusion was
performed on the GE Xeleris workstation. Cardiac retention of 99mTc-DPD was visually scored
according to the classification described by Perugini et al84 as follows: Grade 0 - no visible
myocardial uptake in both the delayed planar or cardiac SPECT-CT scan; Grade 1 - cardiac
uptake on SPECT-CT only or cardiac uptake of less intensity than the accompanying normal
bone distribution; Grade 2 – moderate cardiac uptake with some attenuation of bone signal;
and Grade 3 – strong cardiac uptake with little or no bone uptake.
7.11 STATISTICAL ANALYSIS:
All statistical analysis was performed by myself using SPSS (IBM Corp. Released 2012.
IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp), except survival
analysis which was performed by Aviva Petrie, Head of Biostatistics at the Eastman Dental
Institute, UCL, using SPSS (IBM Corp. Released 2012. IBM SPSS Statistics for Windows, Version
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21.0. Armonk, NY: IBM Corp) and Stata (StataCorp. 2011. Stata Statistical Software: Release
12. College Station, TX: StataCorp LP) and my colleague Dr. Gabriella Captur using REDCap
(Research Electronic Data Capture) electronic data capture tools hosted at the University
College London.155
Normality was tested using the Kolmogorov Smirnov test. All continuous variables
were approximately normally distributed except BNP and Troponin T which were log
transformed to achieve normality for further analysis. Bivariate analysis compared ECV and
pre-contrast T1 with all continuous variables. Pearson’s correlation coefficients are presented
unless otherwise stated. Means are presented ± SD. All reproducibility for cardiac ECV is
presented in the form of intraclass correlation coefficients (ICC). Agreement was ascertained
using the Bland-Altman method where results are presented as mean bias ± 2SD. For
interstudy reproducibility of liver and spleen ECV, only agreement by the Bland Altman and
Pearson’s correlations are given.
The Chi-squared test was used to compare categorical variables between patients and
controls whilst the unpaired t-test was used to compare continuous variables between the
patients and controls. A one-way ANOVA with Bonferroni correction was used to test ECV with
pre-test clinical probability of cardiac involvement described in section 7.2.
Liver, spleen and muscle ECV measurements in healthy volunteers followed a non-
Gaussian distribution and were compared with those in the Amyloidosis population using a
Mann-Whitney U test. In order to examine an association between ECV and SAP score in the
liver and spleen, a Spearman correlation analysis computing a one tailed P-value was
performed.
A goal of this study was to assess the prognostic value of myocardial pre contrast T1
and ECV in Systemic AL Amyloidosis, more specifically the capacity of ECVi compared to ECVb
and pre contrast T1 for discriminating between surviving and dying patients with AL
amyloidosis. ROC curves provide a graphical display for addressing this question by
characterizing the distribution of measurements among patients that die by time t, relative to
the distribution of the parameter among patients that survive. However, conventional ROC
analysis could not be performed because the follow up period was not the same for each
patient. Therefore, time-dependent ROC curves156 were used to assess the capacity of ECVi
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compared to ECVb and pre contrast myocardial T1 for discriminating between surviving and
dying patients with AL amyloidosis. For fixed times (t = 12 months, t = 24 months) and
specificity level, we have compared the sensitivity of ECVi, ECVb and pre contrast myocardial
T1 measurements for detecting patients that will die by time t. For the ROC curves
constructed using the nearest neighbour estimator (NNE), we used a narrow span of λ
(0.25*nobs^(-0.20)) to yield only moderate smoothing. To permit comparison of ROCs by NNE
estimator, a set of simple KM estimator ROC curves for this data at t = 24 months were also
created (see chapter 14 later).
Survival was evaluated using Cox proportional hazards regression analysis, providing
estimated hazard ratios (HR) with 95% confidence intervals (CI) and Kaplan Meier curves.
Linear regression models measured the association between quantitative ECV and other
variables; variance inflation factors (VIF) <3 excluded collinearity. Optimal myocardial T1 and
ECV values were explored by Cox regression, using the median and the 1st or 2nd tertiles as
cut-off values. The two groups resulting from each cut-off were compared using the Harrell’s C
statistic (a measure of discrimination between groups) in order to determine the better model
and thus biomarker for predicting survival. All variables were first explored with univariate
Cox regression. Multivariable models evaluated the independent predictive value of ECV
above other clinically and statistically significant covariates.
For the follow up study, the Wilcoxon Signed Rank Test was used to detect statistically
significant differences in continuous scale cardiac variables between response groups whilst
the McNemar’s test detected statistically significant differences in discrete variables between
response groups. For each patient, amyloid mass was calculated multiplying the ECV x LV mass
whilst cell mass was calculated by multiplying (1-ECV) x LV mass. Difference in amyloid mass
and myocyte cell mass was calculated by subtracting follow-up values from the baseline value.
As these differences were non-normally distributed, results are presented as median and
interquartile range. Comparison between responder groups is assessed using the non-
parametric Kruskal Wallis test.
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8. RESULTS
8. Myocardial ECV as measured by EQ-CMR in Systemic AL Amyloidosis:
This chapter is based on the publication below:150
Banypersad SM, Sado DM, Flett AS, Gibbs SD, Pinney JH, Maestrini V, Cox AT, Fontana M,
Whelan CJ, Wechalekar AD, Hawkins PN, Moon JC. “Quantification of myocardial extracellular
volume fraction in systemic AL amyloidosis: an equilibrium contrast cardiovascular magnetic
resonance study.” Circ Cardiovasc Imaging. 2013; 6(1):34-9
My contribution was consenting, recruiting and scanning all the patients as well as reporting
and analysing all the data. I also wrote the paper.
8.1 Introduction:
As stated earlier in chapter 6, cardiac involvement is the principal driver of prognosis in
this condition and can be the presenting feature of the disease.31 Whilst a constellation of
ECG, echocardiographic and biomarker findings becomes increasingly diagnostic and
prognostic as cardiac amyloidosis progresses, evaluation of early stage cardiac involvement
can be challenging.
Concentration of the serum biomarkers NT-proBNP and Troponin T form the basis of
the Mayo Staging classification33 but are influenced by renal impairment which is present in a
quarter of patients at presentation. ECG criteria, low limb lead voltages23 or fragmented QRS
complexes157 are also predictive, but are confounded by pericardial effusions and conduction
abnormalities. Echocardiographic parameters also predict59, 158, 159 but other co-existing causes
of LVH or diastolic impairment affect interpretation.
Definitive diagnosis of cardiac amyloidosis, which has critical implications for choice of
chemotherapy and management generally, requires cardiac biopsy which is invasive and
prone to sampling error. There are currently no non-invasive tests that can quantify cardiac
amyloid deposits, the need for this having intensified lately with the development of novel
anti-amyloid therapies that will shortly need testing and validation.3
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New imaging modalities are showing promise; DPD scintigraphy, discussed earlier in
section 6.4.4, appears to be able to image cardiac amyloid, though chiefly transthyretin (ATTR)
type,83 whilst imaging with CMR is virtually pathognomonic of amyloid in some patients when
the characteristic global, subendocardial late gadolinium enhancement occurs.89 However,
neither is quantitative.
We therefore tested whether EQ-CMR would accurately measure the degree of
interstitial expansion within the heart.
8.2 Hypotheses:
(1) That EQ-CMR will show a higher ECV in amyloidosis compared to healthy volunteers
(2) That EQ-CMR will be an effective method for quantifying and tracking cardiac amyloid
burden.
8.3 Methods:
Sixty patients from the total AL cohort of 100 mentioned in section 7.2 were recruited.
Four patients who were found to have AF/flutter after they had consented were not excluded.
Of this cohort, 7 (12%) patients were on treatment for hypertension and 6 (10%) had
confirmed coronary artery disease by angiography.
All patients were required to have histological proof of systemic AL amyloidosis by
Congo red histology and immunohistochemical staining, which was obtained through
specimens of kidney (n=17), endomyocardium (n=4), bone marrow (n=8), upper
gastrointestinal tract (n=4), liver (n=1), fat (n=6), spleen (n=1), lung (n=1), rectum (n=8), soft
tissues (n=8), lymph node (n=1) and peritoneum (n=1). This is summarised in figure 23 on the
next page:
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Figure 23: Pie chart showing distribution of tissue biopsies within the patient cohort (n=60).
Healthy subjects (n=82) were the comparator group. As described in sections 7.2 and
7.3, all patients and healthy controls underwent 12 lead ECG. Patients additionally underwent
assays of cardiac biomarkers (NT-proBNP and Troponin T), echocardiography, SAP scintigraphy
including measurement of total body amyloid load, and a 6-minute walk test, although this
was not possible in some patients (n=23, 38%) mainly due to other co-morbid factors (e.g.
arthritis, postural hypotension, peripheral neuropathy) and patient choice. NYHA class and
ECOG status were also assessed using a standard questionnaire.
All patients underwent EQ-CMR using the FLASH IR method of T1 measurement
outlined in section 6.10 and 7.4. A ROI was drawn in the basal septum of the resultant piloted
4-chamber image in all patients as shown in figure 17 on page 46 earlier in this thesis; ROIs
were mid myocardial and excluded subendocardial LGE. Where gadolinium was present, it
was often extensive and therefore impossible to exclude from the ROI (see figure 24 on the
next page). However, where possible, ROIs were also drawn in LGE –ve areas as well as LGE
+ve areas to determine ECV in both. Reproducibility testing was performed as described in
section 7: intrastudy (n=11), interobserver (n=11) and interstudy (n=6) scans were analysed by
myself and Dr. Viviana Maestrini.
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Figure 24: (A) Standard 4-chamber FLASH LGE image; (B) FLASH T1 measurement image at TI of 200ms, demonstrating the difficulty in avoiding areas of LGE when drawing ROIs in cardiac amyloidosis.
Standard CMR parameters of structure (LV mass, left atrial (LA) area with/without
indexing, septal thickness), systolic function (EF, MAPSE, TAPSE) were assessed as well as ECV
calculations. Diastolic function was assessed by echocardiography as described in section 7.8.
Mean ECG QRS voltage in limb and praecordial leads were calculated.160
All statistical analysis was performed as described earlier in section 7.11.
8.4 Results:
Baseline patient and healthy control characteristics are shown in the table 2 on the
next page. Patients were older than healthy volunteers and contained proportionately more
males than females. This slightly increases the control group ECV compared to that of a
gender matched group (see later in this thesis) but there was no statistically significant
increase in ECV with age in the healthy controls.
Patients generally had smaller cavity ventricles and a higher LV mass than healthy
volunteers. Renal function was slightly more impaired compared to healthy volunteers but EF
was not statistically significantly different.
A B
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Characteristic: Patients: Healthy volunteers: P value
Male /female 39/21 41/41 P=0.08
Mean Age ± SD (yrs) 62 ± 10 46 ± 15 P<0.001
Mean Creatinine ± SD (mmol/L) 84 ± 26 74 ± 13 P=0.006
Median NT-pro BNP in pmol/L (IQ range) 121 (20-272) -
Organ involvement
Peripheral/autonomic neuropathy (%) 14 (23) -
Renal involvement (%) 30 (50) -
Cardiac involvement:
None (%)
Probable (%)
Definite (%)
15 (25)
15 (25)
30 (50)
-
-
-
Echocardiography/CMR indices
Mean Indexed LVEDV ± SD (mls) 60 ± 13 72 ± 12 P<0.001
Mean Indexed LVESV ± SD (mls) 19 ± 8 23 ± 7 P<0.001
Mean EF ± SD (%) 67 ± 11 67 ± 5 P=0.44
Mean Indexed LV mass ± SD(g/m2) 94 ± 34 66 ± 13 P<0.001
AF /atrial flutter (%) 4 (7) 0
Table 2: Showing patient characteristics and differences between AL amyloidosis patients and healthy volunteers
The mean ECV in patients with systemic amyloidosis was significantly elevated
compared to healthy controls (0.400 vs 0.254, P<0.001). Mean ECV increased between groups
(P<0.001) from healthy controls to AL with no suspected cardiac involvement (mean ECV
0.276), possible cardiac involvement (mean ECV 0.342) and definite cardiac involvement
(mean ECV 0.488) (figure 25 on the next page).
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Figure 25: Relationship between myocardial ECV and pre-test probability of cardiac AL amyloidosis demonstrated by (A) Bar graph showing mean +/- SD and (B) Individual plots in bins of 0.02 for ECV on y-axis.
ECV and LGE:
LGE prevalence overall was 35/60 (58%). The pattern of LGE was global, sub-
endocardial (n=21), patchy (n=7) and extensive (n=7) (see figure 6 on page 32 for illustrations).
There was no significant difference in the mean ECVs between these groups. LGE presence
was strongly tied to the pre-CMR likelihood of cardiac involvement: no, possible, definite
cardiac involvement LGE prevalences were 0/15 (0%), 6/15 (40%) and 29/30 (99%),
respectively (P<0.001).
ECV correlated strongly with the presence of LGE (P<0.001). All patients with LGE had
an elevated ECV. In 4 cases, sufficient LGE negative areas existed to permit additional LGE
negative ROIs to be drawn. In these cases, the ECV was lower than that derived from adjacent
LGE areas, but still demonstrated substantial elevation. (0.45, 0.44, 0.37 and 0.50 compared
with 0.46, 0.50, 0.44 and 0.53 respectively). Of the 25 patients without LGE, 6(24%) had
elevated ECV, suggesting earlier detection using ECV measurements.
ECV and LV Structure / Function:
ECV correlated with CMR cardiac parameters of LV mass, septal thickness, size (LVESV
and LVESVi) and LAA (see figure 26 on the next page). These findings are summarised in table
3 on page 71.
P<0.001
A B
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Figure 26: Graphs showing the linear relationship between myocardial ECV and (A) Indexed LV mass; (B) Septal thickness; (C) Indexed LV end-systolic volume; (D) Indexed LA area in systemic AL amyloidosis
Figure 27: Graphs showing the relationship between myocardial ECV and (A) Ejection fraction; (B) TAPSE; (C) E:E’ and (D) Mitral E wave deceleration time in systemic AL amyloidosis.
A B
C D
A B
C D
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Measures of cardiac systolic and diastolic function by CMR and echocardiography
respectively, including both simple (MAPSE and TAPSE) and advanced (TDI S-wave, E/E’)
parameters, also showed correlations (see figure 27 on the previous page and table 3 on the
next page); interestingly, hypertrophy was not necessary for ECV elevation - 4 patients
without hypertrophy (2 of whom had LGE) had raised ECVs (0.34, 0.35, 0.42 and 0.52).
ECV and other parameters:
ECV correlated with the biomarkers NT-proBNP and Troponin T (see table 3). ECV was
inversely correlated with mean QRS voltage, particularly in the limb leads (limb leads, R=0.57,
P<0.001; praecordial leads, R=0.30, P=0.02). (See also figure 28 below and table 3 on page 71).
Figure 28: Graphs showing positive, linear relationship between myocardial ECV and (A) Log (base E) BNP; (B) Troponin T and inverse relationship between ECV and ECG (C) Limb lead and (D) Chest lead voltage, in systemic AL amyloidosis. (Note: fewer values for Troponin T as this test was not routinely performed in follow up patients as stated in section 7.6 earlier in this thesis).
Performance in the 6MWT among patients with possible and definite cardiac
involvement by conventional assessment was poorer than for those with no suspected cardiac
involvement (218 vs 207 vs 265m, both P=0.01). ECV weakly correlated with 6-minute walk
A B
C D
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test (R=0.36, P=0.03). There were no differences of ECV with NYHA class or ECOG class. These
results are summarised in table 3 below.
ECV compared against: R P-value
LV Structure by CMR
LV mass 0.52 P<0.001
Indexed LV mass 0.56 P<0.001
Septal thickness 0.56 P<0.001
LA area 0.40 P=0.002
Indexed LA area 0.49 P<0.001
LV Systolic Function by CMR
Ejection Fraction 0.58 P<0.001
MAPSE 0.58 P<0.001
LV end-systolic volume 0.52 P<0.001
Indexed LV end-systolic volume 0.56 P<0.001
TDI-S wave 0.52 P<0.001
LV Diastolic Function by Echo
E:E’ 0.47 P<0.001
IVRT 0.36 P=0.03
E-Deceleration time 0.48 P<0.001
RV Structure & Function by CMR
RV end-systolic thickness 0.40 P=0.005
TAPSE 0.50 P<0.001
Functional Assessment
6-minute walk test 0.36 P=0.03
Biomarkers
Serum NT-pro BNP (logBNP) 0.69 P<0.001
Troponin T 0.53 P=0.006
ECG
ECG Limb Lead mean voltage 0.57 P<0.001
ECG chest lead mean voltage 0.30 P=0.02
Table 3: Showing Pearson’s R correlation coefficients and P-values for relationship between myocardial ECV and standard cardiac parameters in systemic AL amyloidosis
Page 72 of 150
Reproducibility:
The ICC for intrastudy reproducibility of cardiac ECV measurement was 0.99 (0.96-
0.99) with a bias of 0.002 (-0.009 to +0.014). The ICC for interobserver reproducibility was
0.92 (0.76-0.98) with a bias of 0.01 (-0.01 to +0.04). For interstudy reproducibility, the ICC for
myocardial ECVs was 0.96 (0.90-0.99) with a bias of 0.02 (-0.03 to +0.07).
8.5 Discussion:
Amyloidosis is the exemplar of an interstitial disease, the quantity of amyloid in the
extracellular space amounting to kilograms in some patients. Cardiac involvement is a major
cause of morbidity and mortality, particularly in AL type, but there are currently no non-
invasive methods to quantify it.
Here, the ECV was measured using EQ-CMR in systemic AL amyloidosis. ECV was
massively elevated in the patients with definite cardiac involvement but also significantly
higher in patients where conventional clinical testing suggested no cardiac involvement, and
was significantly elevated in a quarter of patients with no LGE.
Expansion of the myocardial ECV represents a non-specific increase in free water
between myocytes, and occurs in a variety of pathologies including focal and diffuse fibrosis,
oedema and amyloidosis. However, the ECV in amyloidosis is higher than in any other disease
generating diagnostic specificity above a certain threshold – for example, in our previous work
(n=238) the highest ECV we have found to date in severe AS, DCM or HCM was 0.37 in a
severe AS patient with previous coarctation repair and a poor LV.161 Here, the average value
for definite cardiac AL amyloid was 0.488 with the lowest value being 0.423. We note however
that the amyloid ROIs frequently included a proportion of areas of LGE, which was excluded in
the previous study. Nevertheless, this data suggests that ECV can detect disease earlier than
conventional testing.
In this study, strong correlations of ECV were also seen with indexed LV mass, LA area,
septal thickness and CMR markers of LV systolic function, and more modest correlations with
measurements of diastolic function. The correlations appear to support many conventional
clinical strategies – for example, that indexed LA area as an excellent indicator of ventricular
disease, the use of limb lead QRS voltages and the use of NT-proBNP and Troponin T in the
Mayo clinical staging system.33 However, biomarker experience shows that single timepoint
ECV measurement is not the whole picture - post chemotherapy, suppression of light chain
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production may trigger a swift change in NT-proBNP levels (usually falls, sometimes
elevation)78, 80 with no ECG or echo changes, suggesting that simple amyloid burden
quantification incompletely reflects myocardial pathology in amyloid.
Mean limb, rather than praecordial, lead QRS voltage on ECG showed an inverse
correlation with ECV. Approximately 50% of patients with cardiac AL amyloidosis have low
QRS voltage (<6mm)52 which has been attributed to “insulation” of the electrical impulse on
the surface ECG due to infiltration. However, it is not seen in all patients and increased QRS
voltages sometimes occur.53 Cardiac ATTR amyloidosis may have far more wall thickening than
AL amyloid, yet low voltages may not occur. Wall thickening in amyloid is the composite of
myocyte volume and amyloid burden, with myocyte volume being a net balance of myocyte
death74, 77 and hypertrophy.162 Conventional testing (such as LV mass) measures the
composite of infiltration and cell volume. Further study with EQ-CMR histological calibration
to derive myocyte volume as well as ECV will be able to answer important questions about the
biology of cardiac amyloid.
A significant correlation with ECV was seen with performance in the 6-minute walk test
but not with NYHA and ECOG performance status, although walking ability in patients with
systemic amyloidosis can be influenced by many non-cardiac factors including peripheral and
autonomic neuropathy, peripheral oedema, pleural effusions due to nephrotic syndrome,
bone pain due to myeloma, and skeletal muscle loss associated with malnutrition.
In summary, ECV is reproducible and tracked a wide variety of markers of disease
activity such as cardiac function and blood biomarkers, linked to patient’s functional
performance, and strongly correlated with limb lead ECG complex sizes. These data suggest
that ECV measurement is picking up infiltration earlier than conventional testing and is a
direct measure of the amyloid burden with potential utility in early diagnosis, disease
monitoring, and potentially as a much needed cardiac surrogate endpoint for the various
promising new therapies for amyloidosis currently in preclinical development and early phase
clinical trials.3, 163
This has recently become particularly relevant with the first-into-man study of the dual
CPHPC-monoclonal antibody trial being run by GSK as described back in section 6.8.2.3 where
the baseline study demonstrated a dramatic reduction in amyloid load measured histologically
in the liver and spleen of mice after treatment. The first-into-man study is currently underway
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and ECV as measured by EQ-MRI is now a surrogate endpoint in determining response to
treatment, based on this work, because SAP scintigraphy is no longer useful once circulating
SAP has been depleted by CPHPC administration. ECV is therefore the only non-invasive
measure of extracellular compartment (and by inference, amyloid load).
As stated already, a limitation of this study is the lack of histological correlations. In
previous work, we have correlated diffuse fibrosis with ECV, but only 4 patients in our present
cohort had undergone cardiac biopsy, and only one of these was contemporaneous, being
performed within 4 months of the CMR study. Precise calibration of ECV with histological
estimation of amyloid burden is desirable but challenging, as often in this multisystem disease
other organs are biopsied before cardiac involvement is recognised and other organs are
easier to sample. Furthermore, amyloid is patchy, predisposing to biopsy sampling error.
Another limitation is that the patient and control populations were not age and sex matched;
ECV is generally higher in women than men although no significant change with age has been
observed.148
As well as histological calibration, populations with ATTR amyloidosis merit study, as
do the prognostic implications of ECV measurements and their reproducibility (all addressed
later in this thesis). Newer, single breath-hold, T1 measurement techniques permit multislice
mapping and have potential for whole heart quantification,145, 164, 165 holding the promise that
it may be possible to avoid the gadolinium infusion in favour of a dynamic/pseudo equilibrium
method, which would have substantial clinical advantages in terms of simplicity (also
addressed later in this thesis).
8.6 Conclusion:
EQ-CMR using the FLASH IR method in systemic AL Amyloidosis has potential to
become the first, non-invasive quantifier of cardiac amyloid burden.
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9. Extracardiac ECV as measured by EQ-CMR in Systemic AL Amyloidosis:
This chapter is based on the following publication:166
Bandula S, Banypersad SM, Sado D, Flett AS, Punwani S, Taylor SA, Hawkins PN, Moon JC.
Measurement of Tissue Interstitial Volume in Healthy Patients and Those with Amyloidosis
with Equilibrium Contrast-enhanced MR Imaging. Radiology 2013; 268(3): 858-64
My contribution was consenting, recruiting and scanning all the patients as well as reporting
and analysing all the data. I also co-wrote the paper. Authorship reflects a departmental level
agreement between Radiology at UCLH and MRI at the Heart Hospital.
9.1 Introduction:
All organs, not just the heart, are composed of metabolically active cells supported by
an extracellular framework. In health, this architecture provides the medium through which
cells exchange components necessary for intracellular metabolism, and can contribute,
physically and metabolically, to the function of their constituent tissue. In disease, this alters
such that amyloid infiltration causes expansion of the interstitium and thus organ dysfunction.
The liver and spleen are frequently affected in systemic AL amyloidosis. The only
conventional non-invasive quantitative test being SAP scintigraphy, as mentioned previously
in section 6.5. Interstitial expansion in the liver and spleen can be massive but difficult to
measure; one reason for this has been an inability thus far to reliably and accurately quantify
the interstitium. The reference standard of invasive tissue biopsy is limited by its technical
difficulty, complication rate, and sampling error.167 There are alternative non-invasive tests,168
including biomarkers and tissue elastography,169-171 however these are frequently organ
specific or suffer from similar sampling error.
In the previous chapter, we demonstrated how EQ-CMR could be used to calculate the
interstitial expansion in cardiac amyloidosis. We described how this technique creates
equilibrium in gadolinium concentrations between myocardium and blood by use of a primed
gadolinium infusion. However when the heart is at contrast equilibrium, so too are other
tissues, excluding privileged sites such as structures behind the blood:brain barrier. This raises
the possibility of extending the technique from EQ-CMR to EQ-MRI in order to assess the
extracardiac organs and tissues.
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The purpose of this study therefore was to assess liver, spleen and skeletal muscle ECV
in patients with systemic AL Amyloidosis and healthy volunteers.
9.2 Hypotheses:
(1) Liver, spleen and skeletal muscle ECV as calculated by EQ-MRI will be greater in systemic
AL Amyloidosis than in health
(2) Liver, spleen and skeletal muscle ECV as calculated by EQ-MRI will track abdominal organ
amyloid burden.
9.3 Methods:
Sixty-seven patients from the AL cohort described in section 7.2 and 40 healthy volunteers
were recruited. We attempted EQ-MRI using the FLASH IR method described in section 7.4.3.2
in all 40 volunteers and 67 amyloidosis patients, but, because of time limitations, patient
discomfort, breathing and wrap-around artefacts and previous surgical resections, complete
imaging was available as follows:
Liver - 35 healthy volunteers and 56 amyloidosis patients
Spleen - 32 healthy volunteers and 48 amyloidosis patients
Paravertebral muscle - 34 healthy volunteers and 53 amyloidosis patients.
Imaging of all 3 tissues was available in 30 healthy volunteers and 46 amyloidosis patients.
All amyloidosis patients underwent SAP scanning of the liver and spleen as described earlier in
section 7.9. All SAP scans were graded on a scale of 0 (none) to 3 (large load) as described
earlier in section 7.9. ECV calculated as previously and all statistical analysis performed as
described earlier in section 7.11. Interstudy variability for ECV calculations of the liver and
spleen were tested for 6 patients as described in section 7.
9.4 Results:
Baseline characteristics:
As in the last chapter, median age was higher in the patient group at 62 years (range
40-81) for patients and 45 years (range 24-88) for healthy volunteers (P<0.001). There were
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also proportionately more males in the patient group than the healthy volunteers (n=43 vs
n=18, P<0.001).
Liver, spleen and muscle ECV were non-normally distributed and ECVs are presented as
median and interquartile (IQ) range.
Organ ECV in Health and Amyloidosis:
Within the healthy volunteer cohort, there was a statistically significant difference in
individual organ median ECVs: liver ECV was 0.29 (IQ range: 0.27–0.33), spleen ECV was 0.34
(IQ range: 0.32–0.35) and paravertebral muscle ECV was 0.09 (IQ range: 0.08–0.14), P<0.001
(see figure 29A).
In amyloidosis, the median ECVs for each organ also varied significantly: liver ECV was
0.32 (IQ range: 0.28–0.37), spleen ECV was 0.39 (IQ range: 0.35–0.51) and paravertebral
muscle ECV was 0.16 (IQ range: 0.13–0.22), P<0.001. We found a statistically significant
increase in the ECV in amyloidosis patients compared with healthy volunteers for all organs
(see figure 29B).
Figure 29: (A) Graph showing Median ECV values in the liver, spleen and paravertebral muscle in healthy volunteers and (B) Graph comparing median ECVs of healthy volunteers to AL amyloidosis patients for liver, spleen and paravertebral muscle.
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Interstudy correlation for the spleen revealed an r2 was 0.98 with a mean bias of -
0.005 (-0.04 to +0.04) although most of these results were clustered around the normal range
with only 1 outlier result. For the liver, r2 was 0.51 with a mean bias of 0.02 (-0.02 to +0.08).
ECV vs SAP grade:
Matched liver ECV measurement and SAP scintigraphy was available in 56 patients. In
15 cases, SAP imaging demonstrated a congested liver pattern with an increased blood-pool
signal associated with cardiac failure, and in one case, localization of the tracer was equivocal;
this left 40 patients who could be assigned a liver SAP grade - 29 patients received a score of
0, five patients received a score of 2, and six patients received a score of 3. Liver ECV showed a
positive correlation with SAP score (rs 0.54, P<0.001) (see figure 30A).
We performed matched splenic ECV measurement and SAP scintigraphy in 48 patients.
Six cases were excluded because SAP activity was scored as equivocal leaving: 22 patients
scored 0, eight patients scored 1, seven patients scored 2, and five patients scored 3. As with
the liver, spleen ECV showed a positive (stronger) correlation with SAP score (rs 0.57, P<0.001)
(see figure 30B below).
Figure 30: Graphs showing relationship of median ECV plotted against SAP grade for (A) Liver and (B) Spleen in systemic AL amyloidosis.
9.5 Discussion:
In this study, we used equilibrium MR imaging to define ECV in healthy tissues and to
document variation in ECV between tissues. Such data are vital if ECV is to be used to detect
pathologic processes. We showed significant differences in a disease process that exemplifies
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expansion of the extracellular space (systemic AL amyloidosis), which provides strong proof
that the equilibrium techniques can be successfully applied outside the heart.
Some pharmacokinetic model based ECV estimates exist. Levitt collected data from
earlier experiments to produce a physiologic-based pharmacokinetic model by allowing
estimation of the ECV in organs of a hypothetical standard human. He estimated the
extracellular fluid fraction of the liver and muscle to be 0.23 and 0.15, respectively.172
More recent studies used dynamic contrast-enhanced MR imaging to quantify the
extracellular space and evaluate changes in response to treatment with a tumour disease
model.173 Dynamic contrast-enhanced MR imaging is a complex technique that is prone to
substantial measurement error, and application is limited to only one tissue site.174 A direct
comparison of equilibrium MR imaging and dynamic contrast-enhanced MR imaging ECV has
not yet been made; however, other authors who used dynamic contrast-enhanced MR
imaging reported ECVs of 0.2–0.3 in healthy liver175 and ECVs of 0.106–0.115 in skeletal
muscle.176 The estimates of ECV from pharmacokinetic modelling and dynamic contrast-
enhanced MR imaging are consistent with each other and with our equilibrium MR imaging
results.
In this study, we compared a disease-specific, in-vivo probe for extracellular amyloid
deposition. SAP scintigraphy is the current reference standard for evaluation of systemic
amyloidosis and has enabled wider assessment of organ amyloid involvement. Unlike
histological analysis, SAP scintigraphy can be used to monitor changes in whole organs over
time. These results demonstrated that an increase in tissue amyloid burden, assessed by SAP
scintigraphy, was associated with an increase in tissue ECV. Therefore, equilibrium MRI
imaging may be a useful non-invasive tool for amyloid assessment and potentially therapeutic
monitoring with the added advantage of not exposing the patient to radiation.
Disease evaluation and quantification with SAP scintigraphy requires specific expertise,
and it is only available in highly specialized centres. As described in sections 6.4.4 and 6.5
earlier, the high atomic mass of the SAP molecule (125 kDa) also favours evaluation in tissues
with a fenestrated endothelium, such as the liver and spleen, where the large molecule is able
to pass into the interstitium. Hence, SAP scintigraphy provides little information about
amyloid deposition in skeletal muscle and myocardium.
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This study had several limitations. The FLASH–based T1 mapping technique is
complicated and time-consuming. Although the bolus-with-infusion protocol used in this
study provided steady-state equilibrium in all tissues of interest, prolonged contrast infusions
are not practical for clinical imaging. Our preliminary experimental findings concur with other
authors’ findings by showing that steady-state equilibration is reached approximately 15 to 20
minutes after administration of contrast bolus with infusion.147 Future protocols may
incorporate equilibrium-phase imaging after a shorter delay.
The ideal comparator for this study would have been histological assessment of the
liver extracellular space. Histological techniques to quantify extracellular collagen matrix do
exist; automated collagen proportionate area measurement showed good association with
other indices of diffuse liver fibrosis when applied to the liver.177 However, collagen-
proportionate area measurements in the healthy liver are around 2%–3%,178 which is much
lower than our ECV estimate. This difference is most likely because the extracellular collagen
matrix occupies only part of the extracellular space within the liver. Current histological
techniques are unable to directly measure the ECV because the process of tissue sampling and
preparation almost certainly alters tissue ECV.
Equilibrium MRI evaluation of ECV is not specific to an aetiological class of disease. In
addition to amyloid deposition and diffuse fibrosis, tissue ECV may be elevated by interstitial
oedema or an inflammatory infiltrate. Although these potential confounders could not be
specifically excluded in this study, cases that demonstrated a congested pattern of activity on
SAP scintigraphy were excluded from the SAP and ECV correlation.
It should be noted that healthy volunteer and amyloidosis patient groups were not
matched for age or sex. As mentioned in the previous chapter, mean myocardial ECV in
healthy women is around 4% higher than in healthy men but there is no change with age.148
This has not been assessed in other organs. In this study, the higher ratio of women in the
healthy group (18 men, 22 women) compared with the amyloidosis group (43 men, 24
women) may have reduced the difference in mean ECV measured between these groups. To
minimize such bias, future studies should ensure that groups are matched for sex.
Although we assessed equilibrium MR imaging in one disease, it is worth noting that
amyloidosis forms part of a larger set of conditions where extracellular disruption and
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expansion leads to organ dysfunction e.g. liver cirrhosis. The application of equilibrium
imaging in these organs could potentially provide a new biomarker for disease evaluation
9.6 Conclusion:
EQ MRI allows ECV of abdominal organs to be calculated; ECV is higher in systemic AL
amyloidosis compared to healthy volunteers and tracks organ amyloid burden.
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10. Technical Development – Refining Clinical Applicability:
My contribution was consenting, recruiting and scanning all the patients as well as reporting
and analysing all the data as first operator. I supplied the entire amyloid component of the 2
technical development papers which I co-wrote with other colleagues within the department
during the time of my MD.179, 180
10.1 Introduction:
In the previous two chapters 8 and 9 in this thesis, we have shown how the EQ-CMR
method uses high resolution FLASH-IR sequences at increasing inversion times to produce a T1
measurement for heart, blood, liver, spleen and skeletal muscle. The ECV is then calculated as
previously described in section 6.10. This technique has advantages in that it is not vendor
specific and is used in everyday clinical practice to obtain high resolution late gadolinium
enhancement images.
However, there are a number of factors which limit its clinical utility in the current
format. Firstly, there exist a number of ways where error may be introduced; patients are
frequently short of breath, not only from the cardiac dysfunction due to amyloidosis, but also
as a result of pleural and pericardial effusions. The FLASH method of T1 measurement,
although high resolution, can be a problem for many patients because of the length of time
required to breath-hold for one sequence; add to this that there are 9 sequences for the heart
with a further 9 sequences repeated for the liver and spleen. This leads to image degradation
because of breathing artefact as well as “ghosting” from the effusions. Indeed, the worst case
scenario is patients being unable to undergo the research sequences at all.
Secondly, because it is a multi breath hold technique, patients may take a slightly
different breath-hold with each sequence, altering not only position of the resultant image,
but also affecting the R-R interval during the breath-hold (NB: a relatively stable R-R interval is
necessary to accurately apply the heart rate correction). Furthermore, once the images have
been obtained, the post processing is laborious, involving drawing a ROI on multiple images
and a manual curve fit to the data points to calculate the TI of interest, plus correction, as
extensively described in section 6.10. It is also ideal to try and avoid areas of LGE where
possible and it is likely that this would vary between different operators using this technique.
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Finally, there is the issue of the cumbersome gadolinium infusion. We calculate the
ECV using the formula outlined in section 6.10. This formula holds true as long as a steady-
state equilibrium of gadolinium concentration exists between the plasma and the tissue
extracellular space i.e. elimination of the normal gadolinium kinetics (see figure 18 in section
6.10). We achieve this with EQ-CMR using a primed infusion of gadolinium commenced at
15mins post bolus. Recent work however, suggests that a “window of opportunity” may arise
at 15mins post bolus, where a dynamic equilibrium or “pseudoequilibrium” may exist because
renal excretion of gadolinium is slower than the free movement of gadolinium between blood
and tissue extracellular compartments.165, 181 Imaging (T1 mapping) at this time may allow an
accurate ECV to be calculated, saving approximately 45 minutes per scan, and sparing the
patient from 30 minutes of a 0.0011 mmol/kg/min infusion of gadolinium; such a technique
would clearly greatly enhance the applicability of ECV assessment further in the clinical
setting.
However, there are concerns that if the timing of the image acquisition is not
consistently accurate, that this would adversely affect the resultant ECV; the ECV does
gradually rise linearly with time as a result of normal gadolinium kinetics.182 Moreover, this
bolus only technique has only been tested in healthy volunteers181 and only very recently in
some cardiac disease states.183 It has crucially not been tested in patients with systemic
amyloidosis which adds its own, almost unique, set of problems because of how amyloid
affects normal gadolinium kinetics; normally and in most disease states, it is the blood and not
the myocardium which has the highest concentration of gadolinium in the first few minutes
after the bolus injection - in cardiac amyloidosis however, the opposite is observed. Whilst
the mechanism for the observation is unclear, it is thought that a high free water content
within the amyloid matrix in the heart, rapidly extracts gadolinium from the plasma into the
myocardial interstitium – this produces the pathognomonic reversed nulling seen on TI scouts
as described in section 6.4.5.
This chapter therefore first evaluates how the FLASH T1 measurement technique was
made more clinically applicable by reducing breath-hold times for the patients by using the
ShMOLLI T1 mapping sequence recently devised by Oxford. Finally, I describe how the
technique was further refined by removal of the gadolinium infusion whilst still maintaining
accuracy.
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10.2 Hypotheses:
1. ECV derived using the ShMOLLI technique will closely match ECV derived from the FLASH
technique.
2. ECV derived without a gadolinium infusion (ECVb) would correlate with ECV calculated using
the infusion (ECVi)
10.3 Methods:
10.3.1 Comparison of FLASH ECV vs ShMOLLI ECV:
Our group acquired the ShMOLLI sequence in 2011, therefore only 50 of the 100 AL
Amyloid patients outlined in section 7.2 underwent EQ-CMR of the heart using both FLASH IR
and ShMOLLI T1 mapping methods and 13 of these also had liver and spleen ECV by both
methods (n=12 for spleen as 1 patient had a splenectomy). All scans were analysed as
described previously and ECV results at equilibrium calculated by myself.
ShMOLLI ECV results were compared for correlation (Pearson’s) and agreement (Bland
Altman) with ECVs derived using the histologically validated FLASH technique.
10.3.2 Comparison of Equilibrium vs Pseudoequilibrium ECV:
Fifty-one patients from the AL Amyloid cohort described in section 7.2 underwent full
EQ-CMR with ShMOLLI T1 mapping and all patients additionally had a ShMOLLI T1 map at 15
minutes post bolus. The T1 was measured in the basal septum in the 4-chamber slice and in
aortic blood and the mean cardiac ECVb and ECVi calculated. Bland Altman analysis was used
to assess agreement between the 2 methods and Pearson’s correlation coefficient used to
assess correlation.
10.4 Results:
10.4.1 Comparison of FLASH ECV vs ShMOLLI ECV:
There was a correlation between FLASH and ShMOLLI ECV for the heart with an R2 of
0.86. Tests for agreement showed a bias of -0.03 (-0.13 to +0.05) for FLASH. All values except
1 fell within the 2 SDs (see figure 31 below):
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Figure 31: FLASH vs ShMOLLI reproducibility (Left) Scatterplot showing the correlation of the 2 myocardial ECVs; (right) Bland Altman graph showing agreement of the 2 myocardial ECVs.
Liver ECV by FLASH also correlated well with ShMOLLI values with an R2 of 0.80. There
was good agreement between the 2 methods with a bias of -0.04 (0.12 – 0.03) for FLASH. As
above, all values except 1 fell within the 2 SDs (see figure 32 below).
Figure 32: FLASH vs ShMOLLI reproducibility (Left) Scatterplot showing the correlation of the 2 Liver ECVs; (right) Bland Altman graph showing agreement of the 2 Liver ECVs.
There was good correlation and agreement between FLASH and ShMOLLI methods for
ECV of the spleen with an R2 of 0.95 and a bias of -0.007 (-0.07 – 0.05) for FLASH. Once again, I
acknowledge that the majority of data points lie at the lower end of the ECV spectrum. All
values fell within the 2 SD limits (see figure 33 on the next page):
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Figure 33: FLASH vs ShMOLLI reproducibility (Left) Scatterplot showing the correlation of the 2 Spleen ECVs; (right) Bland Altman graph showing agreement of the 2 Spleen ECVs.
10.4.3 Comparison of Equilibrium ECVi vs Pseudoequilibrium ECVb:
Mean ECVb and ECVi were both 0.45 (SD 0.12). Both correlation and agreement were
good with a R2 correlation coefficient of 0.88 and a minimal bias of -0.008 (-0.08 to +0.07) (see
figure 34 below). The scatter plot shows little spread at ECVs of less than 0.45 and slightly
wider spread with higher ECVs.
Bland Altman analysis revealed an equal spread of results above and below the
identity line with the vast majority of values falling within the 2 SD limits:
Figure 34: ECVi vs ECVb (Left) Scatterplot showing the correlation of myocardial ECVi and myocardial ECVb; (right) Bland Altman graph showing agreement of myocardial ECVi and myocardial ECVb.
Page 87 of 150
10.5 Discussion:
Correlation and agreement were assessed between FLASH EQ-CMR and ShMOLLI EQ-
CMR methods of ECV calculations for heart (n=50), liver (n=13) and spleen (n=12) ECV. FLASH
and ShMOLLI ECV values showed excellent correlation with each other for heart, liver and
spleen ECV, all yielding an R2 of ≥ 0.8. Agreement was also very good across heart, liver and
spleen ECVs with the largest mean difference being 0.04 for liver ECV. This suggests that the
EQ-CMR using ShMOLLI is an equally accurate method for ECV quantification when compared
to the histologically validated and current gold standard FLASH method, with the significant
advantage however of being more patient friendly, having better clinical applicability and
having a much less laborious off-line analysis. Additionally, interstudy reproducibility has since
been performed, demonstrating that ShMOLLI ECV carries better reproducibility than FLASH
ECV (see figure 35 below).179
Figure 35: Bland Altman graph showing agreement for interstudy reproducibility of myocardial ECVs using the ShMOLLI method. Adapted from Fontana M et al179
We assessed ECVb and ECVi in 51 patients with systemic AL Amyloidosis and compared
the results for agreement and correlation. There is a strong, linear correlation and strong
agreement between the 2 values suggesting that ECVb is a comparable marker to ECVi but
carries the significant advantage that it is does not require the infusion of gadolinium,
rendering it a much shorter technique, easier for patients to perform and less cumbersome
for the operator. It also opens up the practical possibility of whole heart mapping, which
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would require only 3 sequences in either long axis or short axis to acquire all 17 segments of
the heart.
These findings are contrary to other published work. A study of n=20 per various
cardiac diseases concluded that in high ECV diseases i.e. > 0.40 (e.g. cardiac amyloid, MI), ECVb
consistently overestimates compared to ECVi. The bias for ECVb > 0.40 was +0.04, compared to
-0.004 here for ECVb > 0.40.180 The study concluded, perhaps because of the large amount of
amyloid predominating in the subendocardium, that gadolinium was still diffusing into the
myocardium at 15 minutes rather than being at true equilibrium – hence, a longer wait may
be necessary to obtain a more accurate ECV. This observation appears now less marked but
still present as evidenced by the scatter at high ECVs. Ultimately, as a diagnostic tool, ECVb is
likely to be adequate, but for follow up or research purposes where the most accurate result
is needed, an infusion may be necessary.
For the FLASH vs ShMOLLI comparison, there were smaller numbers for liver and
spleen ECV compared with cardiac ECV. This was because there was initially no expertise
regarding how to image the liver using the ShMOLLI, as this had only been validated in the
heart. Secondly, there was a brief period when our department experienced a generic
problem with imaging the liver due to several artefact problems and ShMOLLI liver maps were
not performed therefore during this period. This was eventually tracked down to be a broken
coil element that was causing error despite passing Siemens quality control.
Finally, ECVb and ECVi have not been validated against histology in amyloidosis. Both
have been validated against collagen volume fraction in aortic stenosis though. Histological
validation for systemic amyloidosis remains work in progress. There has been recent evidence
to support the role of ECVb in prognosis184 but this will be explored later in this thesis.
10.6 Conclusions:
1. EQ-CMR using ShMOLLI to calculate cardiac and extracardiac ECV is as accurate in systemic
AL amyloidosis as the FLASH method, but is much more clinically applicable, reproducible and
easier to use for patients and operators. Histological validation is required.
2. ECVb can be used instead of ECVi when assessing systemic AL amyloidosis. Again,
histological validation is required.
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11. Pre Contrast T1 mapping in Systemic AL Amyloidosis:
This chapter is based on the publication below:185
Karamitsos TD, Piechnik SK, Banypersad SM, Fontana M, Ntusi NB, Ferreira VM, Whelan CJ,
Myerson SG, Robson MD, Hawkins PN, Neubauer S, Moon JC. “Non-Contrast T1 mapping for
the diagnosis of cardiac amyloidosis.” JACC Cardiovasc Imaging. 2013 Apr;6(4):488-97
All amyloid patients in this study were AL type and were recruited by myself. All scanning,
reporting and analysis was done by myself – authorship reflects the aortic stenosis
contribution to the paper (not included in this thesis) and also a reciprocal department level
agreement between the Heart Hospital and Oxford for early access to ShMOLLI.
11.1 Introduction:
We have so far demonstrated how ECV can be used to quantify organ amyloid burden
in systemic AL amyloidosis. We have also shown in chapter 10 that the ShMOLLI method of
acquiring ECV measurements is superior to the original FLASH IR method. But this is not
always possible in all patients with systemic AL amyloidosis e.g. severe renal impairment.
The main advantage of CMR compared to echocardiography is in myocardial tissue
characterisation, whether that be through the appearance of global subendocardial LGE, the
hallmark for making the diagnosis of cardiac amyloidosis90, 93 or with ECV measurements.
However, many of these patients have significant renal impairment and so the
administration of a gadolinium-based contrast is problematic. Furthermore, the pattern of
LGE may be atypical and patchy as described in section 6.4.5, particularly in early stages of the
disease.90, 91, 186 Therefore, a non-contrast CMR technique that could provide quantitative
assessment of myocardial amyloid load would prove particularly useful in these patients.
Measurement of myocardial T1 relaxation times using non-contrast T1 mapping has
been shown to be useful in the detection of interstitial expansion due to myocardial oedema
and fibrosis.187-190 Furthermore, alterations of T1 times in the liver, spleen, and fat in patients
with systemic AL amyloidosis have been described using low field MRI.191
We explored therefore whether non-contrast T1 mapping using the single breath-hold
ShMOLLI technique would provide diagnostic information in patients with suspected cardiac
AL amyloidosis.
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11.2 Hypothesis:
That pre contrast T1 mapping with the ShMOLLI technique will provide adequate
diagnostic information of the cardiac status in patients with systemic AL amyloidosis.
11.3 Methods:
Fifty-three patients with systemic AL amyloidosis and no contraindications for CMR
were recruited from the cohort described in section 7.2. Histological proof of AL amyloid was
obtained through specimens of: kidney (n=15), bone marrow (n=8), soft tissues (n=8), fat
(n=5), rectum (n=5), endomyocardium (n=4), liver (n=2), lymph node (n=2), upper GI tract
(n=1), lung (n=1), and peritoneum (n=1). See figure 36 below:
Figure 36: Pie chart showing distribution of tissue biopsies within the AL amyloidosis patient cohort (n=53).
Four patients who were found to have AF/flutter after they had consented were not
excluded. Based on the classifying criteria detailed in section 7.2, the amyloid patients were
characterized as having no (n=14), possible (n=11) and definite (n=28) cardiac involvement.
Thirty-six normal volunteers from the cohort in section 7.3 were also recruited.
All subjects underwent pre contrast myocardial T1 mapping with ShMOLLI as part of
their EQ-CMR where a bolus of 0.1mmol/kg of Dotarem™ was ultimately given as described in
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previous chapters. All patients underwent echocardiography for diastolic measures as
described in section 7.8 and all statistical analysis performed as described in section 7.11.
11.4 Results:
Patient characteristics are described in table 4. There were no differences in age, sex
and body surface area between the groups of patients and healthy volunteers. Patients with
definite cardiac amyloid had significantly increased LV mass index (P<0.001) and smaller LV
end-diastolic volume (P=0.001) compared to healthy controls. EF was mildly reduced in
patients with definite cardiac involvement compared to the other groups (P<0.01 for all
comparisons) although values remained within normal limits. There were no differences in
renal function between the 3 groups of systemic AL amyloidosis patients.
Normals
N=36
Amyloid:
No cardiac
N=14
Amyloid:
possible
cardiac
N=11
Amyloid:
definite
cardiac
N=28
P-value
Age 59 ± 4 58 ± 12 65 ± 10 63 ± 10 0.07
Gender (M/F) 22/14 8/6 7/4 20/8 0.85
NYHA class > III (n) - 0 1 2 -
eGFR (ml/min/1.73m2) NA 85 ± 10 74 ± 32 77 ± 20 0.42
LVEDV index (ml/m2) 77 ± 13 59 ± 11 58 ± 9 65 ± 11 <0.001
LVESV index (ml/m2) 20 ± 5 16 ± 5 13 ± 5 25 ± 8 <0.001
EF (%) 74 ± 5 73 ± 6 77 ± 6 62 ±12 <0.001
LV mass index (g/m2) 58 ± 11 69 ± 20 77 ± 20 118 ± 32 <0.001
Table 4: Showing patient characteristics and differences between patients with differing pre-test probabilities of cardiac amyloidosis in systemic AL amyloidosis and healthy volunteers.
Mean pre contrast myocardial T1 as measured by ShMOLLI was higher in patients at 1086
± 90msec, compared to healthy volunteers of 958 ± 20msec (P<0.001). Myocardial T1 times
showed a stepwise elevation as the probability for cardiac involvement increased: 1009 ±
31msec without cardiac involvement, 1048 ± 48msec with possible cardiac involvement, 1140
± 61msec with definite cardiac involvement (see figure 37 on the next page).
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Between group comparisons are summarized in the list below:
Normals vs amyloid without cardiac involvement, P=0.003
Normals vs possible cardiac amyloid, P<0.001
Normals vs definite cardiac amyloid, P<0.001
Amyloid without cardiac involvement vs possible cardiac amyloid, P=0.265
Amyloid without cardiac involvement vs definite cardiac amyloid, P<0.001
Possible cardiac amyloid vs definite cardiac amyloid, P<0.001
Figure 37: Graph showing the relationship between mean pre contrast myocardial T1 time and pre-test probability of cardiac involvement in systemic AL amyloidosis, compared to healthy volunteers.
ROC analysis (see figure 38 on the next page) showed that a pre contrast myocardial
T1 cut-off value of 1020msec using ShMOLLI T1 mapping yielded a 92% accuracy for
identifying cardiac involvement (area under the ROC curve 0.969±0.01, P<0.0001). Based on
this cut-off, 3 patients with possible cardiac amyloid would have been wrongly classified as
having no cardiac involvement (sensitivity 92%). In contrast, there are 3 false positive cases: 3
amyloid patients with no cardiac involvement clinically who have myocardial T1 above the
threshold (specificity 91%).
Page 93 of 150
Figure 38: ROC curve analysis for pre-contrast myocardial T1 times in Systemic AL amyloidosis.
LGE findings and T1 in cardiac amyloid:
There was no evidence of LGE in the group of AL systemic amyloidosis patients without
cardiac involvement.
In the group of patients with possible cardiac involvement, 3 patients had typical
circumferential subendocardial LGE, 1 patient had patchy enhancement, 2 patients had
reversed nulling on T1 scout and 5 patients had no evidence of LGE.
In the definite cardiac involvement group, 1 patient had no evidence of LGE, and
another one had only abnormal kinetics on T1 scout. All other patients in this group had
evidence of LGE (9 circumferential subendocardial, 6 patchy, 11 extensive LGE - involving not
only the subendocardium but also the subepicardial layer).
All patients with patchy enhancement had increased T1 times (above the threshold of
1020ms determined by ROC analysis), irrespective of the clinical classification as possible or
definite cardiac involvement. Furthermore, 2 out of 3 patients with abnormal kinetics on T1
scout also had elevated T1 times. Interestingly, 3 out of 5 patients with possible cardiac
involvement but no discernible LGE, had significantly elevated T1 times and this also applies to
the patients with definite cardiac involvement who had no LGE. Representative examples of
the CMR scans are shown in figure 39 on the next page:
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Figure 39: Cine still, ShMOLLI and LGE images from (Top 3) Healthy volunteer; (middle 3) AL Amyloidosis patient with extensive LGE; (bottom 3) AL Amyloidosis patient with little LGE This image became the front cover of JACC Cardiovascular Imaging, April 2013.
T1 and cardiac function in cardiac amyloid:
There were significant correlations between pre contrast T1 relaxation times and
indices of systolic and diastolic function in the AL amyloidosis cohort. EF decreased (R=-0.57,
P<0.001) and indexed LV mass increased (R=0.58, P<0.001) as T1 times increased, indicating
that the changes in myocardial T1 times reflect to some extent the severity of cardiac
involvement (see figure 40 on the next page). In addition, T1 times increased significantly as
diastolic function worsened, evidenced by the positive correlation between T1 times and E/E’
ratio (R=0.45, P=0.001) and the negative correlation between T1 times and E deceleration
time (R=-0.44, P= 0.002). See also table 5 on the next page:
Cine ShMOLLI LGE
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Figure 40: (Left) Graph showing positive, linear correlation of pre contrast myocardial T1 and indexed LV mass; (right) graph showing inverse correlation between pre contrast myocardial T1 and ejection fraction in systemic AL amyloidosis.
Normals
N=36
Amyloid:
No cardiac
N=14
Amyloid:
possible
cardiac
N=11
Amyloid:
definite
cardiac
N=28
P-value
ShMOLLI T1 (msec) 958±20 1009±31 1048±48 1140±61 <0.001
E:A ratio NA 0.88±0.15 0.97±0.38 1.72±0.81 <0.001
E:E’ ratio NA 7.6±2.3 14.2±4.5 15.4±6.4 <0.001
E dec time (msec) NA 204±42 231±66 174±62 0.03
Table 5: Showing pre contrast myocardial T1 values and echocardiographic markers of diastolic function for patients according to their pre-test probability of cardiac disease in systemic AL amyloidosis and healthy volunteers.
11.5 Discussion:
This study finds that patients with systemic AL amyloidosis show significantly increased
pre contrast myocardial T1 values compared to healthy controls. This increase is tied to the
extent of cardiac involvement and there is increase in T1 times even when involvement is
uncertain or thought not present. Furthermore, pre contrast T1 correlates well with markers
of systolic and diastolic dysfunction, indicating that the changes in myocardial T1 reflect to
Page 96 of 150
some extent the severity of cardiac involvement. T1 mapping appears to be a useful test to
diagnose cardiac involvement in systemic AL amyloidosis.
As mentioned already in this thesis in section 6.7, cardiac involvement portends a poor
prognosis in AL amyloidosis patients. Its detection informs the intensity of therapy in many
cases. The gold standard for diagnosis of cardiac involvement is cardiac biopsy but sampling
error prevents quantification and there can be false negatives. As mentioned in chapter 6,
ECG abnormalities such as low QRS voltages in limb leads (<0.6mV) and poor R-wave
progression in chest leads occur in up to 2/3 of cardiac AL amyloid patients.23, 53
Echocardiography may demonstrate wall thickening, poor longitudinal function, biatrial
dilatation, early diastolic and late systolic dysfunction,63, 192 but only in the advanced stage do
these features become discriminatory over other diseases such as the hypertensive heart.
CMR provides additive information in cardiac amyloid via myocardial tissue
characterization with contrast. The appearance of global, subendocardial LGE and associated
dark blood-pool is characteristic and correlates with prognosis.88-91, 93 Other LGE patterns do
exist as described in section 6.4.5, and LGE may occur even without overt hypertrophy.
However, LGE patterns may be non-specific or only occur in later disease, and require contrast
which may be contraindicated in patients with renal failure which is common in amyloid.193
With the degree of myocardial infiltration present in amyloid, pre contrast T1 mapping
has the potential to detect cardiac involvement and be clinically useful. Changes in T1 times
had previously been demonstrated in the liver, spleen, and fat in amyloidosis using low field
MRI191 and early results supported myocardial changes.86, 194, 195 Here, we build on these
results using the latest, robust and more accurate advanced short breath-hold T1 mapping
technology incorporating a single output colour T1 map196 in a large cohort with robust
controls and demonstrate functional consequences and early disease detection. Although
there are technical differences between the MR sequences used to measure T1 relaxation
times, our results are in agreement with previous work from Hosch and colleagues who found
a 19% increase in T1 times in cardiac amyloid patients compared to normal controls.86
Measurement of T1 times using ShMOLLI T1 mapping has shown very good accuracy
for the detection of cardiac involvement in AL amyloidosis and correlate well with the extent
of systolic and diastolic dysfunction. It is tempting to speculate that pre contrast T1 mapping is
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more sensitive than the LGE technique for the detection of cardiac involvement, as all amyloid
patients with non-typical patchy enhancement had increased T1 values.
This study has similar limitations to previous chapters in this thesis, chiefly that
patients had histologically proven amyloid but not routine endomyocardial biopsies. No
histological correlation with T1 is therefore available. T1 mapping is also of course a
composite value of myocytes and interstitium and does not therefore represent the
interstitium alone; ECV is the better marker for this. Finally, the prognostic value of T1 values
in amyloid was not explored here, but this is assessed in the next chapter.
11.6 Conclusion:
Pre contrast myocardial T1 appears to be a useful test to diagnose the presence and
extent of cardiac involvement in systemic AL amyloidosis.
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12. T1 mapping and Survival in Systemic AL Amyloidosis:
This chapter is based on the publication below:
Banypersad SM, Fontana M, Maestrini V, Sado DM, Captur G, Petrie A, Whelan CJ, Herrey AS,
Gillmore JD, Lachmann HL, Wechalekar AD, Hawkins PN, Moon JC. “T1 Mapping and Survival
in Systemic Light Chain Amyloidosis.” European Heart Journal (2015); 36(4): 244-51.197
An abstract of this work also won $500 at the Young Investigator Awards finals at the
American Heart Association in Dallas when presented on 17th November 2013 and was also
presented at the Young Investigator Awards at SCMR in New Orleans earlier this year on 17th
January 2014. My contribution was recruiting all the patients, reporting and analysing all scans
and writing the paper.
12.1 Introduction:
As mentioned earlier in chapter 6, cardiac involvement in systemic AL amyloidosis is
present in around 50% of patients at presentation and is the principal driver of prognosis.198
Current predictors of survival rely on measuring surrogate rather than direct markers of
interstitial expansion (e.g. serum cardiac biomarkers). ECG criteria such as low limb lead
voltages23 or fragmented QRS complexes157 are also predictive, but are confounded by
pericardial effusions and conduction abnormalities. Echocardiographic parameters also
predict outcome59, 158, 159 but coexisting causes of LVH or diastolic impairment may affect
interpretation.
CMR with LGE imaging adds value in the diagnosis of cardiac involvement in AL
amyloidosis. Altered gadolinium kinetics also shows some correlation with survival.93 In this
chapter therefore, we now consider the predictive power of ECV after primed infusion (ECVi)
with survival. In addition, we also tested the predictive power of ECVb, pre contrast T1 and
post contrast T1.
12.2 Hypotheses:
1. That ECV will correlate with survival
2. That ECV correlates better with survival than pre contrast and post contrast myocardial T1.
Page 99 of 150
12.3 Methods:
The 100 consecutive patients with systemic AL amyloidosis stated in section 7.2 were
recruited (this includes all 60 patients in chapter 8 and all 53 patients in chapter 11). Six
patients, who were found to have AF/flutter once in the scanner after they had consented,
were not excluded.
All patients had histological proof of systemic AL amyloidosis except 2 (2%), who died
before biopsy could be undertaken, but in whom monoclonal gammopathies were present
and the organ distribution of amyloid on SAP scintigraphy was characteristic of AL type.
Histology was performed with Congo red followed by immunohistochemical staining; tissues
examined were: kidney (n=26, 26%), endomyocardium (n=7, 7%), bone marrow (n=13, 13%),
upper gastrointestinal tract (n=7, 7%), liver (n=3, 3%), fat (n=15, 15%), spleen (n=1, 1%), lung
(n=1, 1%), rectum (n=9, 9%), soft tissues (n=12, 12% - included skin, tongue, buccal mucosa,
labia), lymph node (n=3, 3%) and peritoneum (n=1, 1%). See figure 41 below:
Figure 41: Pie chart showing distribution of tissue biopsies within the AL amyloidosis patient cohort (n=100).
As described in chapter 7, all patients underwent 12 lead ECG, assays of the cardiac
biomarkers NT-proBNP and Troponin T, and echocardiography at baseline. Mean ECG QRS
voltage in limb and praecordial leads were calculated.160 Echocardiographic assessment of
diastolic function was performed as described in section 7.8. All patients underwent
conventional CMR and EQ-CMR as previously described in sections 6.10 and 7.4. Standard
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CMR parameters of structure (LV mass, LAA, maximal septal thickness) and systolic function
(EF, MAPSE, TAPSE) were assessed. Pre contrast myocardial values were calculated and the
post contrast T1 map was performed at 15 minutes post bolus and after equilibration so that
the ECVb and ECVi could be calculated.
Some ECV data (n=19 of the 100) pre-dated the availability of ShMOLLI T1 mapping
and had thus utilised multibreath-hold FLASH T1 measurement described in chapter 6.10. But
as we have demonstrated equivalence of these ECVs in chapter 10, these patients are not
excluded from the ECVi data.
That said, these patients did not have an ECVb value or the subsidiary component of
the ECV equation, pre contrast T1; multibreath-hold measurement has been shown to be
inferior to T1 mapping, so accordingly, these were excluded from the sub-analysis comparing
techniques - this particular analysis therefore consists of 81 rather than 100 patients.
ECV and Myocardial T1 results were compared to 54 healthy volunteers who
underwent pre contrast T1 mapping and ECV measurement (bolus and infusion). The number
of patients dead and alive was assessed after a median duration of 23 (Interquartile range: 6-
25) months. Some analysis involved sub-grouping patients into pre-test probability of cardiac
involvement as previously described in section 7.2. All statistical analysis was performed as
stated in section 7.11.
12.4 Results:
Table 6 on the next page summarises baseline characteristics for patients and healthy
volunteers. Within the patient cohort, 14 (14%) patients were on treatment for hypertension;
10 (10%) had confirmed coronary artery disease by angiography, 1 (1%) had had a stroke and
2 (2%) had diabetes.
Page 101 of 150
Characteristic: Patients: Healthy Controls:
P value
Male /female 62/30 25/29 P=0.02
Mean Age ± SD (yrs) 62 ± 10 46 ± 15 P<0.001
Mean Creatinine ± SD (mmol/L) 89 ± 33 74 ± 13 P<0.001
Median NT-proBNP in pmol/L (IQ range) 146 (27-359) -
Median Troponin T in ng/L (IQ range) 0.03 (0.01-0.06) -
ECG/CMR indices
Mean Indexed end-diastolic LV volume ± SD (mls) 60 ± 13 73 ± 12 P<0.001
Mean Indexed end-systolic LV volume ± SD (mls) 19 ± 10 25 ± 7 P<0.001
Mean EF ± SD (%) 67 ± 11 67 ± 6 P=0.42
Mean Indexed LV mass ± SD(g/m2) 97 ± 35 65 ± 15 P<0.001
AF /atrial flutter (%) 6 (7) 0
Table 6: Showing patient characteristics and differences between AL amyloidosis patients and healthy volunteers
Fifty patients were treated with chemotherapy for the first time which comprised
triple therapy with either Cyclophosphamide, Thalidomide and Dexamethasone (CTD) or
Cyclophosphamide, Velcade and Dexamethasone (CVD), depending on local guidelines of
regional NHS Trusts within the UK. Seventeen patients were treated for a 2nd or 3rd time
having relapsed – treatment was either with CVD or a Lenalidomide-containing regimen in
these instances. Nine patients had not received any chemotherapy as there was no clinical
indication (e.g. renal amyloid with established renal failure, isolated neuropathic
presentations) and 24 patients were under stable follow up with no indication for further
chemotherapy at the time of scan.
Twenty-one patients had a pre-test probability of no cardiac involvement, 26 had
possible cardiac involvement and 53 had definite cardiac involvement.
All ECV values are the ECVi from infusion measurement unless otherwise stated.
Healthy controls were younger on average, but our work and others suggests any ECV changes
with age are small compared to amyloid changes.148, 165 There were proportionately more
females in the control vs patient group. This slightly increases the control group ECV and pre
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contrast T1 compared to that of a gender matched group (male vs female: ECV 0.24 vs 0.27,
P<0.001; T1 940 vs 966ms, P=0.006).
ECV
Myocardial T1
Pre contrast Post contrast
LV Structure by CMR R P-value R P-value R P-value
LV mass 0.48 P<0.001 0.43 P<0.001 0.40 P=0.004
Indexed LV mass 0.50 P<0.001 0.43 P<0.001 0.36 P=0.01
Septal thickness 0.61 P<0.001 0.53 P<0.001 0.34 P=0.01
LA area 0.32 P=0.002 0.13 P=0.28 0.29 P=0.043
Indexed LA area 0.30 P=0.005 0.09 P=0.45 0.14 P=0.31
LV Systolic Function by CMR
Ejection Fraction 0.48 P<0.001 0.32 P=0.005 0.20 P=0.17
MAPSE 0.58 P<0.001 0.50 P<0.001 0.23 P=0.10
LV end diastolic volume 0.06 P=0.58 0.12 P=0.30 0.09 P=0.51
LV end-systolic volume 0.31 P=0.002 0.15 P=0.19 0.07 P=0.63
Indexed LV end diastolic volume 0.10 P=0.32 0.17 P=0.14 0.25 P=0.07
Indexed LV end systolic volume 0.32 P=0.002 0.14 P=0.24 0.01 P=0.93
LV Diastolic Function by Echo
E:E’ 0.37 P<0.001 0.25 P=0.03 0.28 P=0.052
IVRT 0.34 P=0.007 0.27 P=0.05 0.19 P=0.28
E-Deceleration time 0.23 P=0.03 0.40 P<0.001 0.05 0.71
RV Systolic Function by CMR
TAPSE 0.57 P<0.001 0.52 P<0.001 0.41 P=0.003
Biomarkers
Serum NT-pro BNP (LnBNP) 0.65 P<0.001 0.58 P<0.001 0.25 P=0.07
Troponin T (LnTropT) 0.52 P<0.001 0.36 P=0.02 0.62 P=0.001
ECG
ECG Limb Lead mean voltage 0.42 P<0.001 0.35 P=0.002 0.03 P=0.98
ECG chest lead mean voltage 0.23 P=0.03 0.12 P=0.28 0.15 P=0.28
Table 7: Showing the Pearson’s correlation coefficients and P values for the correlations of myocardial ECV, pre contrast T1 and post contrast T1 with standard cardiac parameters in patients with systemic AL amyloidosis.
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As in chapter 8, mean cardiac ECV was greater in patients compared to healthy
volunteers with a wider range (0.44 ± 0.12 vs 0.25 ± 0.02, P<0.001) and tracked pre-test
probability of cardiac involvement by conventional parameters (P<0.001).150 Mean pre
contrast myocardial T1 values were raised in patients compared to healthy volunteers (1080 ±
87 ms vs 954 ± 34ms, P<0.001) and also tracked pre-test probability of cardiac involvement
(P<0.001).185 Table 7 on the previous page provides the Pearson correlation coefficients of
ECV, pre contrast and post contrast myocardial T1 compared to other cardiac parameters,
many of which typically change in cardiac amyloid. ECV correlated significantly with 17 of 19;
pre contrast T1 with 12, and post contrast T1 with 10.
With regards late gadolinium enhancement, 25 patients had no LGE, 50 had global
subendocardial enhancement and 10 had extensive enhancement. Eight had patchy
enhancement and 7 had evidence of only altered gadolinium kinetics. ECV correlated
significantly with increasing degrees of late gadolinium enhancement (P<0.001) as shown in
figure 42 below.
Figure 42: Dot plot showing correlation between ECV and late gadolinium enhancement
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ECV correlates with survival:
At follow up (median 23 months), 25 of 100 patients had died. For each potential
predictor, median and tertile cut-points were assessed for predictive power using the Harrell’s
C statistic and the best result presented (see table 8).
Tertile Cut point HR (95% CI) P-value Harrell’s C
ECVi
Tertile 1 0.40 4.67 (1.39 - 15.5) 0.013 0.63
Median 0.45 3.83 (1.53 - 9.61) 0.004 0.66
Tertile 2 0.49 3.61 (1.56 - 8.38) 0.003 0.65
Pre contrast Myocardial T1
Tertile 1 1044ms 5.39 (1.24 - 23.4) 0.02 0.64
Median 1080ms 3.01 (1.08 - 8.44) 0.035 0.62
Tertile 2 1116ms 3.22 (1.30 – 8.04) 0.01 0.63
ECVb Median 0.44 5.09 (1.09 – 23.7) 0.03 0.68
Post contrast T1 Median 565ms 0.45 (0.17 – 1.20) 0.11 0.41
Table 8: Showing the hazard ratios and P-values for the median / tertiles of ECVi, ECVb (median only), pre contrast T1 and post contrast T1 (median only). The Harrell’s C statistic is also shown (a value higher than 0.6 indicates a stronger discriminator).
For ECVi, a median ECV of 0.45 was the best model for assessing survival: HR 3.84 (1.53
– 9.61), P=0.004 (figure 43 on the next page). The survival curve indicates that there is an
approximately 40% chance of death at 23 months in patients with an ECV > 0.45 compared to
15% for ECV < 0.45.
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Figure 43: Kaplan Meier survival curve showing worse survival for patients with an ECVi > 0.45 compared to patients with an ECVi < 0.45 in systemic AL amyloidosis.
For pre contrast myocardial T1, the 1st tertile (cut point 1044ms) was the best model:
HR 5.39 (1.24 – 23.4), P=0.02 (figure 44A). ECVb with median of 0.44 also correlated with
survival, with a HR of 5.09 (1.09-23.7), P=0.04 (figure 44B). Post contrast T1 did not correlate
with survival (HR=0.5, P=0.11).
Figure 44: Kaplan Meier survival curve showing worse survival for patients with (A) a pre contrast myocardial T1 of > 1044msec compared to patients with a T1 of < 1044msec and (B) an ECVb > 0.44 compared to patients with an ECVb < 0.44 in systemic AL amyloidosis.
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When the 3 models (ECVi, ECVb and pre contrast T1) were compared to determine the
best correlator with survival using the Harrell’s C statistic, all 3 performed similarly, although
there was a trend to suggest ECVb was the best model then ECVi, then pre contrast T1
(Harrell’s C statistics: 0.68, 0.65, 0.64 respectively, see also table 8 on page 104).
The time-dependent ROC curves for t=12 months and t=24 months using the NNE
method are shown in figure 45. For comparison, time-dependent ROC curves by Kaplan Meier
analysis for t=24 months are also shown in figure 46. At earlier follow-up times (t=12 months),
the three ROC curves are not dissimilar and ECVi does not provide improved discrimination for
cumulative mortality when compared to ECVb and pre contrast T1. At 24 months, they remain
similar, although the NNE ROC curve for ECVi appears to dominate the ROC curves for both
ECVb and pre contrast T1. This implies that, for any fixed specificity, the ECVi measurement at
later follow up (t = 24 months) is a more sensitive marker. In contrast, the Kaplan Meier based
ROC curves exhibit monotonicity violations.
Figure 45: ROC curves for ECV and pre contrast myocardial T1 measurements against survival in AL amyloidosis at t=12 months and t=24 months. Panels A-C show the ROC curves for t=12 months using the nearest neighbour estimator (NNE) and panels D-F show these for t=24 months.
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Figure 46: Panels A-C show the ROC curves for t=24 months based on direct use of the simple Kaplan-Meier estimator. Comparison to the NNE-based ROC curves in figure 45 shows how KM-based ROC curves exhibit monotonicity violations.
ECV independently predicts survival:
Table 9 below shows the univariate data for ECV with measures of systolic and diastolic
function and serum biomarkers.
Measure HR (95% CI) P-value
ECV 3.84 (1.51-9.60) P<0.001
EF 0.95 (0.92-0.98) P=0.001
MAPSE 0.80 (0.71-0.90) P=0.001
TAPSE 0.81 (0.75-0.88) P<0.001
Indexed LVEDV 0.95 (0.92-0.99) P=0.005
Indexed LVESV 1.02 (0.98-1.06) P=0.32
NT-proBNP 5.80 (2.75-12.2) P<0.001
E:E’ 1.09 (1.05-1.14) P<0.001
E-deceleration time 1.00 (0.99-1.01) P=0.29
LGE 10.3 (1.39-76.5) P=0.02
ECG (limb) 0.92 (0.77-1.08) P=0.35
ECG (chest) 0.99 (0.97-1.02) P=0.83
Table 9: Showing hazard ratios and 95% confidence intervals for the univariate analyses of all measures against mortality.
After excluding collinearity (VIF < 3), ECVi > 0.45 remained significantly associated with
mortality (HR=4.41, 95% CI 1.35-14.4; P=0.01) in multivariate Cox models that included
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measures of systolic and diastolic function and serum biomarkers: E:E’, diastolic dysfunction
grade (≥2), EF and LnNT-proBNP (Troponin was not available in all patients). E:E’ and NT-
ProBNP also remained independently predictive (see table 10 below).
Measure HR (95% CI) P-value
ECV 4.41 (1.35-14.4) P=0.01
EF 1.02 (0.98-1.07) P=0.37
E:E’ 1.08 (1.02-1.15) P=0.009
NT-proBNP 4.41 (1.66-11.8) P=0.003
Diastolic dysfunction grade 0.31 (0.10-0.92) P=0.03
Table 10: Showing hazard ratios and 95% confidence intervals for the multivariate analysis for ECV, EF, E:E’, NT-proBNP and diastolic dysfunction grade against mortality.
12.5 Discussion:
Myocardial ECV in cardiac AL amyloid correlates with mortality. When dichotomised, a
higher than mean ECV associates with roughly a 35-40% increased chance of death at 23
months compared to lower ECV patients, despite therapy. Pre contrast T1 also correlated with
survival. Both correlated with baseline clinical parameters. In practice, since the two
parameters are typically measured together, their combination may confer diagnostic
confidence.
In chapters 8 and 11, I have previously described both ECV measurement and pre
contrast T1 mapping as potential, non-invasive techniques for directly measuring the cardiac
disease burden in AL amyloid.150 Here, those earlier results are now strengthened by higher
numbers and additionally, prognostic significance of the biomarkers is demonstrated even
with therapy.
The marked survival prediction power of ECV lends support to ECV as a key amyloid
biomarker. Prior work in non-amyloid patients, where ECV likely measures diffuse fibrosis, has
also showed predictive power – in 1176 consecutive CMR referral patients over a median of
1.3 years follow up, 24 deaths occurred with ECV carrying a hazard ratio of 1.52 (1.21 – 1.89)
for admissions with heart failure and all cause mortality.199 Here, we have demonstrated that
ECV adds incremental value over and above existing clinical markers when risk-stratifying
patients. Unfortunately, it was not possible to include NYHA class in the multivariable model
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because this information was not available in all patients due to other factors limiting exertion
such as peripheral and autonomic neuropathy due to systemic amyloidosis. Additionally, the
limited number of deaths limits very extensive multivariable analysis so this may not
represent the optimal multivariable model.
We used an arbitrary categorization for the presence or otherwise of cardiac amyloid.
The Mayo staging system is the most recognized predictor of survival in systemic AL
Amyloidosis.33 In new presentations, median survival was reduced from 26 months to 10
months when either NT-proBNP or Troponin T was raised and reduced further still to only 3
months if both biomarkers were raised, although the authors are in the process of further
refining this model with inclusion of values for serum free light chain concentration.200 Our
survival data in the 45 patients scanned at presentation would support these findings but is
currently underpowered (only 17 deaths) to determine incremental benefit of ECV; this
remains work in progress.
ECV is predictive regardless of treatment status and indeed irrespective of whether
patients are presenting at diagnosis or years into the disease process. Some patients in the
cohort had modest ECV increases (ECV 0.30-0.40) without any other evidence of cardiac
involvement (no LGE, no wall thickness increase and no biomarker elevation) reinforcing our
original findings that even patients classified as having no cardiac amyloid do have raised ECVs
suggestive of low grade cardiac disease. A plausible role for aggressive therapy in such
patients to prevent progression to overt cardiac disease can be entertained.150
The simpler, pre contrast myocardial T1 technique does not require a contrast agent
and shows promise,185 particularly as 20-30% of patients with systemic AL amyloidosis have an
eGFR < 30ml/min at presentation. In these patients, the Mayo staging system is in part
confounded by elevation of serum biomarkers due to renal dysfunction. Here, pre contrast
myocardial T1 by ShMOLLI is an alternative to ECV. It is an equally strong correlator with
survival but as mentioned earlier, it represents a composite signal from cells and interstitium,
not just the interstitium alone like ECV. Some work may be needed to derive normal pre
contrast T1 values in patients with renal impairment due to non-amyloid related pathologies.
An additional issue is that ECV measurement appears more independent of measurement
approaches (magnet field strength, manufacturer, precise sequence details) and is likely to be
easier to standardize as a clinical test than pre contrast T1.
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From a practical perspective, the bolus only approach to ECV (ECVb) was as good, if not
better, a predictor of survival as the more cumbersome infusion ECVi. We showed in chapter
10 (and indeed our group has shown that in most disease states) that ECVb carried excellent
agreement with ECV at true equilibrium.180 This study suggests that the ECVb passes a key
clinical utility test of being prognostic. Post contrast T1 however, was not useful either at
baseline or to predict outcome.
Limitations of the study are that patients were followed up for different time periods
and are at different disease and treatment stages, with treatment here reflecting current UK
practice. Unfortunately, the cause of death is not always known in these patients as the
National Amyloidosis Centre only generally receives notification of death rather than
information on the formal cause of death. However, it is widely accepted that most death due
to AL amyloidosis are cardiac in nature. Studies looking to correlate ECV change with
haematological and clinical response as well as histology in AL amyloidosis, have yet to be
performed. Whole heart ECV calculations were not possible in this study because of through-
planing of blood pool in areas of thinner myocardium towards the apex but as technology
advances with motion correction T1 mapping sequences, this will become possible. The
advent of PSIR imaging is of growing importance in LGE imaging. As stated earlier, the number
of events limits extensive analysis. That said, these are nevertheless hard endpoints and the
rule of 10 regarding multivariable analysis can be relaxed in these settings.201 Whether ECV
and pre contrast T1 – which are not entirely concordant - provide different pathological
insights is at this stage unknown.
12.6 Conclusion:
1. ECV (ECVb and ECVi) tracks established disease, detects early cardiac involvement and
independently correlates with survival.
2. The pre contrast T1 mapping method is shown to be almost as prognostic, providing
options for patients in renal failure.
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13. Pilot Study – Follow up EQ-CMR in Systemic AL Amyloidosis:
This preliminary study, led by me, assessed the change in ECV amongst a small number of AL
patients who we were able to re-scan when they re-attended the National Amyloidosis Centre
a few months after their 1st scan, for their follow up appointments. As the numbers were small
at the time, this continues to be work in progress.
13.1 Introduction:
Change over time in cardiac amyloid is not well understood. The way myocytes
hypertrophy or die and why such changes may be triggered by infiltration (or the free light
chains) remain opaque. Treatment with chemotherapy or stem cell transplantation aims to
reduce or eradicate abnormal circulating free light chains in order to reduce or stop further
amyloid production; a CR is associated with improved morbidity and mortality.135 The
absence of systolic and diastolic dysfunction at presentation can carry a much more
favourable prognosis than once thought.202 If light chain production is switched off, NT-
proBNP can fall nearly immediately despite no overt functional changes in the short term.
Amyloid regression (well described in AA with inflammation switch off) does not occur
substantially in the heart, although the liver and spleen may be more responsive.
Our knowledge has been hampered by poor measurement. Wall thickness and LV mass
measure myocytes and interstitium: changes may be reflective of either compartment and
compensatory processes clearly occur, impeding understanding. Cardiac biopsy has shown
regression of cardiac amyloid histologically but this is invasive.203 We have demonstrated in
this thesis how ECV can measure the interstitial expansion in multiple organs in systemic AL
amyloidosis. We sought to explore therefore whether ECV could detect any significant
changes in organ amyloid burden at different time points in the disease.
13.2 Hypothesis:
That ECV would change over time and with the success of therapy in AL amyloid.
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13.3 Methods:
Of the 100 systemic AL patients, 26 were scanned a 2nd time as described in section 7.2
at one of their subsequent follow up appointments. As the patient follow up appointments
are booked well in advance, it was not always possible to coincide an EQ-CMR scan as part of
their next appointment because of the other clinically necessary investigations described in
chapter 7. Hence, the follow up periods for each patient are different and their “starting
points” are all at different stages of disease. The median duration of follow up was 12 months.
All 26 patients were scanned with the identical protocol to their first scan and the ECVs
for heart, liver and spleen were calculated. The patients were then categorised as follows:
(1) Complete responders - normal light chain levels (CR) throughout follow up (n=9)
(2) Partial responders - normal light chain levels for part of follow up period (n=8)
e.g. (a) commenced 6 months of chemo to CR; (b) Relapsed
(3) Non-responders - abnormal light chain levels throughout follow up (n=9)
e.g. (a) Failed to respond to chemo; (b) Stable PR
Mean difference in ECV for each organ was calculated for groups 1 to 3 and the results
compared for statistically significant differences as described in section 7.11.
13.4 Results:
In group 1, there was a statistically significant improvement in LV mass, LA area and
mean chest lead QRS voltage in patients who had normal light chains for the whole follow up
period (see table 9). In terms of ECV, spleen ECV improved from 0.42 to 0.37 (P=0.02) but
cardiac and liver ECV did not show any statistically significant changes.
In group 2, there were no statistically significant changes, whilst in group 3, the LVEDV
showed an improvement from 115ml to 94ml (P=0.04). These results are summarised in table
11 on the next page:
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Responder group
Baseline Follow up P-Value
Myocardial T1 (msec)
1 1089 1084 0.219
2 1159 1101 0.125
3 1080 1089 0.688
Cardiac ECV
1 0.43 0.40 0.300
2 0.48 0.54 0.125
3 0.52 0.57 0.500
Liver ECV
1 0.33 0.31 0.313
2 0.38 0.36 0.813
3 0.37 0.35 0.578
Spleen ECV
1 0.42 0.37 0.039
2 0.58 0.47 0.439
3 0.44 0.46 0.813
ECG Limb Lead (mV)
1 4.0 3.6 0.355
2 4.8 4.8 0.893
3 3.5 3.5 0.866
ECG chest lead (mV)
1 12.4 11.4 0.016
2 12.4 11.7 0.152
3 11.4 11.3 0.915
LV mass (g)
1 182 159 0.004
2 212 198 0.301
3 222 219 0.997
Indexed LV mass (g/m2)
1 102 84 0.004
2 103 97 0.310
3 120 122 0.910
LA area (cm2)
1 24 22 0.050
2 31 30 0.931
3 25 25 0.281
Indexed LA area (cm2)
1 13 11 0.027
2 15 15 0.930
3 14 14 0.426
Table 11: Showing the change in value from baseline to follow up of various markers of systemic AL amyloidosis, split according the responder status. P-values also shown.
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When the overall trend was considered, a scatter plot of cardiac ECV changes
suggested that generally, there was an improvement in ECV in patients with normal light
chains (group 1) and a gradual worsening of ECV in the incrementally worse responder groups
2 and 3 i.e. an apparent downward linear trend (see figure 47); however, this was not
statistically significant on formal linear regression analysis (P=0.132). Additionally, the Kruskall
Wallis test, used to assess the distribution of cardiac ECV changes across the responder
groups, did not reveal a statistically significant result (P=0.356).
Figure 47: Scatter plot of individual results showing change in myocardial ECV (y-axis) against responder status (x-axis) in systemic AL amyloidosis. (NB: some patients had exactly the same ECV, but still displayed as 1 point on the graph).
Six patients in group 1, 7 in group 2 and all patients in group 3 had LGE at baseline. This
did not qualitatively change at follow up (P=0.107).
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Amyloid and cell mass were calculated as described in section 7.11 (baseline – follow
up i.e. a +ve value denotes a decrease at follow up). Table 12 below shows the difference in
amyloid mass and myocyte mass between the responder groups:
Responder group
Median amyloid mass difference in grams (IQ range)
Median cell mass difference in grams (IQ range)
1 +14.7 (+3 to +20) +7.7 (+5 to +13)
2 -3.2 (-14 to +8) +17.6 (+6 to +28)
3 -6.1 (-17 to +5) +8.4 (0 to +11)
Table 12: Showing the median difference from baseline to follow up in amyloid mass and myocyte cell mass across the 3 responder groups.
When the trend across responder groups was analysed using the Kruskal Wallis test,
the difference in amyloid mass only just reached statistical significance (P=0.05) while
difference in cell mass did not (P=0.305).
13.5 Discussion:
In this pilot study, 26 patients underwent follow up EQ-CMR scans after a mean
duration of 12 months and ECVs for heart, liver and spleen calculated. Group 1 demonstrated
the most statistically significant changes, although other groups are confounded by a higher
bias of death and therefore not reaching follow up, a limitation common to all studies
assessing treatment response. There was a higher risk of death in group 3 compared to group
1 (HR 0.153, P=0.014 for group 1 by Cox regression analysis) in keeping with current
knowledge. Group 2 showed no statistically significant results.
Spleen ECV showed an improvement from 0.42 to 0.37; cardiac and liver ECV changes
did not reach statistical significance. These findings would suggest that the spleen may be a
useful, early marker of disease response. This may be because of an intrinsic property of
splenic tissue that enables it to recover more readily from disease processes, similar to the
liver. Perhaps because embryologically-speaking, the spleen is a primarily haematological
organ, the immune system is more readily able to clear amyloid deposited within it.
Considering that splenic tissue shows a higher range of ECV than the other organs (0.24 –
0.85) and was a stronger correlator with SAP grade in chapter 9 than liver, this lends further
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support to the theory that the spleen appears to be a more accurate marker of interstitial
disease change systemic AL amyloidosis and this may be useful in pharmacological studies
attempting to achieve amyloid regression. Histology would be necessary to confirm this.
Group 1 also showed a statistically significant reduction in LV mass and LA area, both
indexed and non-indexed. One could speculate that this is due to a reduction in the
interstitium as there is a concomitant decrease in cardiac ECV, though again, cardiac histology
is required to corroborate these suspicions. The reduction in LA area may represent a crude
marker of improved diastology.
Mean chest lead ECG voltage also showed a decrease from 12.4mV to 11.4mV in group
1 (P=0.02). This might be reflective of a reduction in LVH with a sustained complete
haematological response as there is corresponding decrease in LV mass in this group.
However, the long accepted theory has been that interstitial expansion explains the reduction
in QRS voltages as electrical activity is “insulated” – therefore, any suspected amyloid
regression should cause an increase in QRS voltage. So these findings raise questions about
whether the interstitium truly insulates electrical activity or whether in fact surface ECG
changes in amyloidosis reflect a balance between the source of the electrical activity (i.e. the
myocytes) and the interstitium.
In group 3 (the non-responder group), cardiac ECV rose from 0.52 to 0.57. Although
this did not reach statistical significance, we speculate that this may suggest continued
interstitial expansion due to ongoing amyloid deposits in the heart when patients do not
achieve a CR. Interestingly, LV mass showed little change in this group, which might suggest
myocyte necrosis at the expense of interstitial expansion, a potential mechanism to explain
the worsening clinical status in this group; this should be explored further with histological
studies, although as mentioned earlier, follow up studies in this non-responder group are
generally hampered by the higher incidence of death
There was a borderline statistically significant trend towards a regression in actual
gram mass of amyloid with improving light chains. Albeit without histological support, this is
the first evidence of regression of the interstitial expansion seen in systemic amyloidosis and
provides the framework for developing a highly accurate marker of measuring treatment
response in the condition. Difference in cell mass did not reach statistical significance and it
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was not possible to assess differences in extra cardiac organs as the mass of these organs was
not known.
Clearly, the biggest limitation here is small numbers after categorising into 3 responder
groups, as well as the bias towards death in the groups who do not achieve a complete
haematological response. There is also the issue of lead time bias as the patients were not
followed up for the same amount of time or from the same point in the disease process so it is
difficult to draw many meaningful conclusions. A further limitation, common to the whole
thesis, is the lack of corroborating evidence from histological studies. However, we are able to
detect some changes in the different responder groups and these findings have potential to
provide further insights into the biological mechanisms underlying the disease process in AL
amyloid. The clinical relevance of these findings is once again emphasised when one considers
the in vitro data and now the ongoing human trials of the dual CPHPC-monoclonal antibody
trial.
13.6 Conclusion:
ECV may represent the initial stages of the first non-invasive tool to demonstrate
amyloid regression and progression in systemic AL amyloidosis.
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14. DISCUSSION AND CONCLUSIONS
14.1 Background and Hypotheses Explored:
Cardiac amyloidosis remains challenging to diagnose and to treat. Key ‘red-flags’ that
should raise suspicion include clinical features indicating multisystem disease and concentric
LV thickening on echocardiography in the absence of increased voltage on ECG; the pattern of
gadolinium enhancement on CMR appears to be very characteristic. Confirmation of amyloid
type is now possible in most cases through a combination of immunohistochemistry, DNA
analysis and proteomics.
But whilst developments in chemotherapy have improved the outlook in AL
amyloidosis, the prognosis of patients with cardiac involvement remains very poor and senile
cardiac amyloidosis is probably greatly under-diagnosed. Although a variety of novel specific
therapies are on the near horizon, with potential to both inhibit new amyloid formation and
enhance clearance of existing deposits, current treatment remains mainly supportive,
focussed on diuretic therapy.
The inability to reconcile advances in treatment strategies with improved outcomes
reflects our incomplete understanding of the biology of the disease process. For example,
whilst well recognised, it is not known why cardiac ATTR amyloidosis is better tolerated than
cardiac AL amyloidosis, despite the much thicker hearts? Or why exactly ECGs show low
voltages in the limb leads? A number of theories have been put forward e.g. myocyte necrosis
in AL amyloidosis, or toxicity from circulating immunoglobulin light chains, or an acute (e.g.
myocardial oedema) on chronic process in advanced stages of cardiac AL Amyloidosis, but
none has ever been definitely proven.
This is likely because no technique has been thus far able to feasibly image or quantify
the interstitium in this archetypal interstitial disease. Being able to do so would undoubtedly
improve our knowledge of the differences between amyloid types and may allow therapy to
be better targeted. Recently, MRI and more specifically, EQ-CMR has been shown to measure
the interstitium in a variety of cardiac diseases.
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As a result of the work during my MD:
1) I have demonstrated that ECV measurement in Systemic Amyloidosis is feasible and I have
refined the technique as described in chapter 10 to make it clinically more applicable.
2) I have defined a reference range of ECVs that track increasing levels of cardiac disease
within the amyloidosis population as well as in multiple other organs.
3) I have applied the pre contrast myocardial T1 technique to assess amyloid deposition in the
heart, which will have a role in the 25-30% of AL amyloidosis patients with eGFR < 30ml/min
where gadolinium administration would be relatively contraindicated.
4) I have shown how ECV and T1 correlate with mortality in this disease and demonstrated
that clinical outcome may be changed by identifying those patients who may benefit the most
from early treatment.
14.2 Refining Clinical Applicability of EQ-CMR in Systemic Amyloidosis:
Before the work in this thesis, measurement of the ECV technically required
equilibration of contrast concentrations between blood and myocardium, which can be
achieved precisely using a somewhat cumbersome primed contrast infusion (ECVi).147 The
patient would have to undergo a 30 minute infusion of gadolinium contrast which was very
disruptive to clinical workflow and quite tedious and cumbersome for a population of patients
who are particularly unwell. We found that it was only possible to scan 6 patients per day
using this method, whereas our clinical CMR list currently scans 10 patients in the same time
frame – a significant financial burden. Additonally, the FLASH IR method of T1 measurement
required 9 breath-holds before and after contrast administration, each lasting around 14
seconds to acquire a map of a single slice. It is also not an accurate method for evaluation of
tissues with longer T1, particularly that of blood prior to contrast administration.
During my MD, we entered into a collaboration with the Oxford group, who had
written a new T1 mapping sequence, the ShMOLLI. This allows a T1 map of a selected slice to
be generated in a single breath-hold over 9 heart beats. We found it to be faster and more
reproducible than the the FLASH IR method in amyloidosis. By applying this technique to EQ-
CMR in chapter 10 and validating its use in calculating ECV in systemic amyloidosis, what
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previously took 8-10 mins now takes under 1 minute as a result of my work. Similarly, I have
shown in chapter 10 that ECV can be calculated sufficiently accurately through delayed study
following administration of a bolus of gadolinium (ECVb).180 As a result of this work, the overall
scan time is reduced by a further 30 minutes, making the scan clinically more applicable.
Both of these advances have made the assessment of ECV a much simpler “add on” to
a clincal CMR scan, only requiring in addition, a haematocrit measurement.
14.3 ECV Measurement:
Before my work, there was no non-invasive quantifier of interstitial expansion in
systemic amyloidosis. There had been some work assessing interstitial expansion in other
disease using different models such as partition coefficients and dynamic contrast-enhanced
MR.
My work has now demonstrated that ECV can be calculated in the basal to mid septum
in cardiac AL amyloidosis and it shows a large increase in the myocardium. ECV Disease-
specific correlations have been identified. The technique was also used to assess the liver,
spleen and biceps ECV in amyloidosis patients healthy volunteers as well as a preliminary
evaluation of its role in tracking disease progress or improvement at follow up.
Novel information has also been gained as a result of this work as I showed in chapter
8 that when ROIs are drawn in LGE positive and LGE negative areas in the same patient, the
ECV, whilst lower in LGE negative areas, is still not normal.150 Because of this, although T1
mapping is now more mature with sequences available on all platforms, it is difficult to
compare ECV and T1 to LGE and PSIR imaging which can be helpful with LGE imaging in
amyloid, is not available on all platforms.
14.4 Native Myocardial T1:
Prior to my work, there had been only case reports of T1 analysis using the Look-
Locker method to assess T1 times in cardiac amyloidosis. The Look Locker method is prone to
error because of long breath-hold times, T1 measurements in different phases of the cardiac
cycle and being more T1 and heart-rate dependent.
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My work has provided reference ranges for myocardial T1 times in cardiac amyloidosis
using the more robust T1 mapping sequence, the ShMOLLI. We found a large increase in pre
contrast T1 values in patients with increasing amyloid deposition. This work has opened up
the door to non-invasive analysis of amyloid burden by cardiac MR in patients with renal
failure which was hitherto not possible because of the risk of NSF from gadolinium. The
combination of this with ECV has provided information on some of the biology in AL amyloid.
14.5 Clinical Insights and Potential:
Although trends are changing, assessment of cardiac amyloidosis currently relies
predominantly on echocardiography which, as an imaging modality, has a much lower spatial
resolution than MRI. The main determinants of severity are septal thickness and LV mass,
which incompletely reflect the biology at work and systolic / diastolic dysfunction which likely
represent more advanced stages of the disease.
The ECV shows the potential to fill this gap not only for the heart, but also the liver and
spleen and may permit earlier identification of cardiac disease which may save lives. The pilot
studies suggest possible biological explanations for some hitherto unexplained observations
(e.g. low QRS voltages on ECG) and also speculate upon the role of ECV in monitoring
response to therapy. But most importantly, it has the potential to be an independent
predictor of survival, additive to current prognosticators such as the Mayo classification. This
would save patient lives not only from the disease itself, but possibly even reduce some of the
treatment-related mortality.
However, it is important to balance this with recognition of the current limitations. I
have not been able to histologically validate the technique so the technique cannot yet be
deemed to be a true non-invasive quantifier of cardiac amyloid burden. Removal of the need
for a gadolinium infusion has made the technique more clinically applicable as a diagnostic
tool. However, debate remains whether ECVb would be sufficiently accurate for follow up and
monitoring of disease progression.
Furthermore, although ECV has emerged as independently predictive of survival in
multivariate analysis, it is unclear how much this will impact on and change current clinical
management which relies heavily on Troponin T and NT-pro BNP; if one considers ECV as a
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biomarker, it is more expensive than Troponin T and NT-pro BNP although if one considers the
additional information gained from cardiac MRI as a whole with ECV as an add-on, this may
represent a more cost-effective strategy overall – further studies are needed. There are also
standardisation challenges yet to be addressed across different centres with MRI.
14.6 Future Work:
This thesis has looked at the diverse uses of CMR T1 mapping based methodology to
assess systemic amyloidosis. Work is needed to establish histological validation of ECV with
cardiac histology. This is challenging not only because of the obvious invasive nature of biopsy,
but also because of the need to correlate the timing of biopsy within an acceptable time-
frame of the EQ-CMR scan, something which is not easy when patients live so far away. The
ideal staining method to differentiate amyloid from fibrosis in a manner which is still
quantifiable by computer software remains an ongoing challenge too.
ECV measurements in extracardiac organs also requires standardising. The ideal
method of T1 mapping the liver and spleen remains undetermined and where to draw ROIs in
the liver requires universal agreeement. Further work is also needed in evaluating the role of
ECV and T1 in ATTR amyloidosis – this is already work in progress.
From an MRI perspective, the T1 mapping sequences are constantly improving e.g. the
ShMOLLI sequence currently does not correct for any motion artefacts which makes it more
likely to result in partial voluming with blood at the edges of a myocardial ROI – such
sequences are work in progress.204 There has also been very little work comparing the
reproducibility T1 and ECV across multiple sites and using MRI equipment from differing
vendors.
From a more general perspective, myocardial T1 and ECV assessment is a new field
and there is little agreement between groups as to what terminology should be used e.g.
extracellular volume (ECV), extracellular volume fraction (ECVF), myocardial volume of
distribution (Vd(m)) have all been used by different groups to describe the same thing over the
last 2-3 years. An initiative from this hospital (Prof. James Moon) has therefore set up a T1
mapping development group which has now met 7 times and has drafted proposed
preliminary recommendations for everyone in the field to use as a baseline guide.
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My work has triggered a number of key changes and progressions, specifically:
1. The NAC now routinely transfers patients to the Heart Hospital for CMR scanning and T1
mapping to calculate ECV which was not previously the case.
2. ECV results now play a key role in the weekly MDT meetings when determining the timing
and choice of treatment.
3. My work comparing ECV to SAP scanning in AL amyloidosis has laid the groundwork for
similar research in comparing ECV with DPD scanning in ATTR amyloidosis. This work has
already begun and the preliminary findings were shortlisted at the Young Investigator
Awards at the 2014 AHA scientific sessions in Chicago, USA.
4. My work with ECV in the liver and spleen in AL amyloidosis has attracted the attention of
the pharmaceutical industry who are now using ECV of the liver and spleen as an endpoint
for their first in man study of therapy in systemic AL amyloidosis, following my
presentation of this data at the International Amyloidosis Symposium in 2012.
14.7 Conclusion:
This thesis has provided further insight into the field of myocardial T1 mapping and
ECV assessment and highlighted their roles in detecting cardiac and systemic amyloidosis
involvement at a much earlier stage and also more sentivitively. It shows the huge potential of
these techniques and lays a path for future work in the field to ultimately benefit and improve
patient outcomes from this rare but fatal disease.
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186. Banypersad SM, Moon JC, Whelan C, Hawkins PN, Wechalekar AD. Updates in Cardiac Amyloidosis: A Review. J Am Heart Assoc. 2012;1:e000364.
187. Dall'Armellina E, Piechnik SK, Ferreira VM, Si QL, Robson MD, Francis JM, Cuculi F, Kharbanda RK, Banning AP, Choudhury RP, Karamitsos TD, Neubauer S. Cardiovascular magnetic resonance by non contrast T1-mapping allows assessment of severity of injury in acute myocardial infarction. J Cardiovasc Magn Reson. 2012;14:15.
188. Dass S, Suttie J, Piechnik SK, Ferreira V, Holloway C, Robson MD, Watkins H, Karamitsos T, Neubauer S. Non-contrast T1 mapping characterizes the myocardium beyond that achieved by late gadolinium enhancement in both hypertrophic and dilated cardiomyopathy. J Cardiovasc Magn Reson. 2012;14(Suppl 1):O27.
189. Bull S, White SK, Piechnik SK, Flett A, Ferreira V, Loudon M, Francis JM, Neubauer S, Moon JC, Myerson S. Pre-contrast T1 mapping for detection of myocardial fibrosis in asymptomatic and symptomatic aortic stenosis. J Cardiovasc Magn Reson. 2012;14(Suppl 1):P93.
190. Ferreira VM, Piechnik SK, Dall'Armellina E, Karamitsos TD, Francis JM, Choudhury RP, Friedrich MG, Robson MD, Neubauer S. Non-contrast T1-mapping detects acute myocardial edema with high diagnostic accuracy: a comparison to T2-weighted cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 2012;14:42.
191. Benson L, Hemmingsson A, Ericsson A, Jung B, Sperber G, Thuomas KA, Westermark P. Magnetic resonance imaging in primary amyloidosis. Acta Radiol. 1987 Jan-Feb;28(1):13-5.
192. Liu D, Niemann M, Hu K, Herrmann S, Stork S, Knop S, Ertl G, Weidemann F. Echocardiographic evaluation of systolic and diastolic function in patients with cardiac amyloidosis. Am J Cardiol. 2011 Aug 15;108(4):591-8.
193. Bergesio F, Ciciani AM, Santostefano M, Brugnano R, Manganaro M, Palladini G, Di Palma AM, Gallo M, Tosi PL, Salvadori M. Renal involvement in systemic amyloidosis--an Italian retrospective study on epidemiological and clinical data at diagnosis. Nephrol Dial Transplant. 2007 Jun;22(6):1608-18.
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195. Robbers LF, Baars EN, Brouwer WP, Beek AM, Hofman MB, Niessen HW, van Rossum AC, Marcu CB. T1 mapping shows increased extracellular matrix size in the myocardium due to amyloid depositions. Circ Cardiovasc Imaging. 2012 May 1;5(3):423-6.
196. Piechnik SK, Ferreira VM, Dall'armellina E, Cochlin LE, Greiser A, Neubauer S, Robson MD. Shortened Modified Look-Locker Inversion recovery (ShMOLLI) for clinical myocardial T1-mapping at 1.5 and 3 T within a 9 heartbeat breathhold. J Cardiovasc Magn Reson. 2010 Nov 19;12(1):69.
197. Banypersad SM, Fontana M, Maestrini V, Sado DM, Captur G, Petrie A, Piechnik SK, Whelan CJ, Herrey AS, Gillmore JD, Lachmann HJ, Wechalekar AD, Hawkins PN, Moon JC. T1 mapping and survival in systemic light-chain amyloidosis. Eur Heart J. 2015 Jan 21;36(4):244-51.
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16. APPENDIX
16.1 Acknowledgements:
A list of collaborators for this work is provided below. There are many people I would
like to thank for their help with this work. First and foremost, I thank Dr. James Moon for his
supervision and for spearheading the collaboration between the Heart Hospital and the Royal
Free Hospital. I would like to thank Sarah Anderson, Dr. Daniel Sado and Dr. Derek Hausenloy
for teaching me how to perform clinical CMR and Dr. Daniel Sado and Dr. Andrew Flett for
teaching me how to perform T1 mapping based CMR. I am also thankful to Dr. Viviana
Maestrini, Dr. Marianna Fontana and all the other fellows for their assistance during the scans
during my 3 years at the unit. My thanks also to Sandy Gardner and Neelu Jauffur for booking
the patients in for scans and for their patience when frequently rearranging their slots... and a
special thank you to Neelu who also became my wife during this time.
At the Royal Free Hospital, I would like to thank Prof. Philip Hawkins for his supervision
and support in creating this collaboration and getting the project off the ground. I also thank
Drs. Gillmore, Wechalekar and Lachmann for teaching me about systemic amyloidosis over
this last 3 years. I am grateful to the nursing staff, in particular Thirusha Lane, Lisa Rannigan
and Darren Foard for their help in coordinating the MRI scans with the multiple investigations
at the National Amyloidosis Centre. I must also thank Ramon Lamarca for rearranging patient
bookings and slots in order to coincide with free MRI slots, as well Sherla Isaacs and
Christianne Guillotte for arranging all the transport for the patients.
More distantly, I thank Prof. Sir Mark Pepys whose academic prowess was responsible
for attracting the attention of industry to the department. I must also thank Mr. Duncan
Richards for constantly supporting the project and for remaining actively involved in directing
the project through regular meetings at the National Amyloidosis Centre.
Lastly, I would like to thank my parents and my brother Dr. Vishal Banypersad for their
support over this 3 years.
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List of Collaborators:
James Moon,1,2 Reader and honorary Consultant in Cardiology: Primary supervisor.
Prof. Philip Hawkins,3 Clinical Lead National Amyloidosis Centre: Secondary supervisor.
Dr. Viviana Maestrini,1 Clinical Research Fellow: Technical Development
Dr. Marianna Fontana,1,3 Clinical Research Fellow: Technical Development
Dr. Daniel Sado,1 Clinical Research Fellow: Technical Development
Dr. Jennifer Pinney,3 Clinical Research Fellow: Cardiac and extracardiac ECV
Dr. Simon Gibbs,3 Clinical Research Fellow: Cardiac and extracardiac ECV
Dr. Chris Venner,3 Clinical Research Fellow: Cardiac and extracardiac ECV
Dr. Jason Dungu,3 Clinical Research Fellow: Pilot ATTR
Dr. Ashutosh Wechalekar,3 Consultant Haematologist: Cardiac and extracardiac ECV
Dr. Julian Gillmore,3 Consultant Nephrologist: Cardiac and extracardiac ECV
Dr. Helen Lachmann,3 Consultant Nephrologist: Cardiac and extracardiac ECV
Dr. Stefan Piechnik,4 Physicist: Pre contrast T1, Technical Development
Dr. Matthew Robson,4 Physicist: Technical Development
David Hutt,3 Nuclear Physicist: Pilot ATTR
Dorothea Gopaul,3 Nuclear Physicist: Pilot ATTR
Dr. Vanessa Ferreira,4 Clinical Research Fellow: Technical Development
Dr. Theodoros Karamitsos,4 Clinical Research Fellow: Pre-contrast T1
Prof. Stefan Neubauer,4 Professor of Cardiology: Technical Development
Dr. Steve Bandula,5 Clinical Research Fellow: Extracardiac ECV
Dr. Shonit Punwani,5 Consultant Radiologist: Extracardiac ECV
Dr. Stuart Taylor,5 Consultant Radiologist: Extracardiac ECV
Sarah Anderson, Sandy Gardner, Neelu Jauffur, Paula Campbell, Jodee Cooper, Queen’s
Square Enterprises Staff: CMR Logistics6
Ramon Lamarca, Sherla Morris, Sam Ramiz, Christianne Guillotte, Leon Peet, Thirusha
Lane, Annie Hughes, Alicia Bangova: National Amyloidosis Centre Logistics3
Aviva Petrie,7 Head of Biostatistics: Statistical Analysis
All the patients who took part in the research programme
Page 145 of 150
1. The Heart Hospital, 16-18 Westmoreland Street, London, W1G 8PH.
2. Institute of Cardiovascular Science, University College London, London, WC1E 6BT.
3. Centre for Amyloidosis and Acute Phase Proteins and National Amyloidosis Centre, Royal
Free Campus, University College London, Rowland Hill Street, London, NW3 2PF.
4. Oxford Centre for Clinical Magnetic Resonance Research, Department of Cardiovascular
Medicine, University of Oxford, Oxford, OX3 9DU.
5. University College Hospital, Department of Radiology, Gower Street London, WC1E 6BT.
6. QSE, The heart Hospital Imaging Centre, The Heart Hospital, 16-18 Westmoreland Street,
London, W1G 8PH.
7. Biostatistics Unit, UCL Eastman Dental Institute, 256 Grays Inn Road, London WC1X 8LD.
16.2 List of Original Findings:
1. T1 and ECV are measurable in cardiac amyloid
2. T1 and ECV track disease and early disease is detected prior to other changes
3. Cardiac, liver, spleen and skeletal muscle ECV are all raised in systemic AL amyloidosis
compared to normal and are easily quantified using EQ-CMR
4. ECV and pre contrast myocardial T1 predict survival in systemic AL Amyloidosis
5. Change over time can be detected
6. ECV and T1 track disease burden in ATTR amyloidosis and provide insights into biology
7. Technically, the EQ-CMR technique using the FLASH IR method is reproducible but the
ShMOLLI method of T1 mapping is superior for calculating ECV and pre contrast T1
8. The bolus only approach is sufficient and is equally prognostic as the infusion method
16.3 Location of Research:
All of the CMR imaging was performed at the Heart Hospital Imaging centre (16-18
Westmoreland Street, London, W1G 8PH). All nuclear imaging, Echocardiography, ECG, blood
tests and 6 minute walk testing were all performed at the National Amyloidosis Centre.
16.4 Personal Contribution:
My contribution to this work is documented below:
Page 146 of 150
1) Obtained minor ethics amendment.
2) Recruited, personally scanned, clinically reported and performed the research post
processing on all of the patients.
3) Took preliminary hypotheses, proved them, developed new hypotheses and followed the
science as it developed
4) Taught the technique to Dr. Marianna Fontana and played second author roles in the
subsequent ATTR studies.
5) Performed most of the statistical analysis presented in this thesis.
6) Wrote this thesis.
16.5 Supervision:
Primary supervisor: Dr James Moon
Secondary supervisor: Prof. Philip Hawkins
16.6 Funding:
This work was funded by GlaxoSmithKline. 16.7 Prizes / Awards:
May 2012 – Won €1000 as Young Investigator Award winner, International Symposium for
Amyloidosis, Groningen, The Netherlands.
Nov 2013 –Won $500 as AHA Young Investigator Award finalist, Dallas, USA.
Jan 2014 – SCMR Young Investigator Award finalist, SCMR, New Orleans, USA.
16.8 Publications:
1. Banypersad SM, Fontana M, Maestrini V, Sado DM, Captur G, Petrie A, Piechnik SK, Whelan
CJ, Herrey AS, Gillmore JD, Lachmann HJ, Wechalekar AD, Hawkins PN, Moon JC. “T1
mapping and survival.” European Heart Journal (2015); 36(4): 244-51.
Page 147 of 150
2. Sado DM, Maestrini V, Piechnik SK, Banypersad SM, White SK, Flett AS, Robson MD,
Neubauer S, Ariti C, Arai A, Kellman P, Yamamura J, Schoennagel BP, Shah F, Davis B,
Trompeter S, Walker M, Porter J, Moon JC. “Non-contrast myocardial T1 mapping using
cardiovascular magnetic resonance for iron overload.” J Magn Reson Imaging. 2014 Aug 8.
doi: 10.1002.
3. Fontana M, Banypersad SM, Treibel TA, Maestrini V, Sado DM, White SK, Pica S, Castaletti
S, Piechnik SK, Robson MD, Gilbertson JA, Rowczenio D, Hutt DF, Lachmann HJ, Wechalekar
AD, Whelan CJ, Gillmore JD, Hawkins PN, Moon JC. “Native T1 Mapping in Transthyretin
Amyloidosis.” JACC Cardiovascular Imaging. 2014; 7(2), 157-65
4. Pinney JH, Smith CJ, Taube JB, Lachmann HJ, Venner CP, Gibbs SD, Dungu J, Banypersad SM,
Wechalekar AD, Whelan CJ, Hawkins PN, Gillmore JD. “Systemic amyloidosis in England: An
Epidemiological study.” Br J Haem 2013 May;161(4):525-32. doi: 10.1111/bjh.12286.
5. Bandula S, Banypersad SM, Sado D, Flett AS, Punwani S, Taylor SA, Hawkins PN, Moon JC.
Measurement of Tissue Interstitial Volume in Healthy Patients and Those with Amyloidosis
with Equilibrium Contrast-enhanced MR Imaging. Radiology. 2013 May 14
6. Pinney JH, Whelan CJ, Petrie A, Dungu J, Banypersad SM, Sattianayagam P, Wechalekar A,
Gibbs SD, Venner CP, Wassef N, McCarthy CA, Gilbertson JA, Rowczenio D, Hawkins PN,
Gillmore JD, Lachmann HJ. “Senile systemic amyloidosis: clinical features at presentation
and outcome.” J Am Heart Assoc. 2013 Apr 22;2(2):e000098
7. White SK, Sado DM, Fontana M, Banypersad SM, Maestrini V, Flett AS, Piechnik SK, Robson
MD, Hausenloy DJ, Sheikh AM, Hawkins PN, Moon JC. “T1 Mapping for Myocardial
Extracellular Volume Measurement by CMR: Bolus Only Versus Primed Infusion
Technique.” JACC Cardiovasc Imaging. 2013 Apr 5
8. Sado DM, White SK, Piechnik SK, Banypersad SM, Treibel T, Captur G, Fontana M, Maestrini
V, Flett AS, Robson MD, Lachmann RH, Murphy E, Mehta A, Hughes D, Neubauer S, Elliott
PM, Moon JC. “The Identification and Assessment of Anderson Fabry Disease by
Cardiovascular Magnetic Resonance Non-Contrast Myocardial T1 Mapping.” Circ Cardiovasc
Imaging. 2013 1;6(3), 392-8.
Page 148 of 150
9. Karamitsos TD, Piechnik SK, Banypersad SM, Fontana M, Ntusi NB, Ferreira VM, Whelan CJ,
Myerson SG, Robson MD, Hawkins PN, Neubauer S, Moon JC. “Noncontrast t1 mapping for
the diagnosis of cardiac amyloidosis.” JACC Cardiovasc Imaging. 2013 Apr;6(4):488-97
10. Banypersad SM, Sado DM, Flett AS, Gibbs SD, Pinney JH, Maestrini V, Cox AT, Fontana M,
Whelan CJ, Wechalekar AD, Hawkins PN, Moon JC. “Quantification of myocardial
extracellular volume fraction in systemic AL amyloidosis: an equilibrium contrast
cardiovascular magnetic resonance study.” Circ Cardiovasc Imaging. 2013 Jan 1;6(1):34-9
11. Fontana M, White SK, Banypersad SM, Sado DM, Maestrini V, Flett AS, Piechnik SK,
Neubauer S, Roberts N, Moon JC. “Comparison of T1 mapping techniques for ECV
quantification. Histological validation and reproducibility of ShMOLLI versus multibreath-
hold T1 quantification equilibrium contrast CMR.” J Cardiovasc Magn Reson. 2012 Dec 28;
14: 88-96
12. Banypersad SM, Moon JC, Whelan C, Hawkins PN, Wechalekar AD. Updates in cardiac
amyloidosis: a review. J Am Heart Assoc. 2012 Apr;1(2):e000364
13. Sado DM, Flett AS, Banypersad SM, White SK, Maestrini V, Quarta G, Lachmann RH,
Murphy E, Mehta A, Hughes DA, McKenna WJ, Taylor AM, Hausenloy DJ, Hawkins PN,
Elliott PM, Moon JC. Cardiovascular magnetic resonance measurement of myocardial
extracellular volume in health and disease. Heart. 2012 Oct;98(19):1436-41
14. Dungu J, Sattianayagam PT, Whelan CJ, Gibbs SD, Pinney JH, Banypersad SM, Rowczenio
D, Gilbertson JA, Lachmann HJ, Wechalekar A, Gillmore JD, Hawkins PN, Anderson LJ. The
electrocardiographic features associated with cardiac amyloidosis of variant transthyretin
isoleucine 122 type in Afro-Caribbean patients. Am Heart J. 2012 Jul;164(1):72-9
Page 149 of 150
16.9 Abstract Presentations:
16.9.1 Oral Presentations:
1. Cardiac Amyloid Burden Assessment by T1 Mapping Predicts Survival in Systemic AL
Amyloidosis: A 2 year follow up study
- SCMR Young Investigator Award, SCMR, New Orleans, USA, Jan 2014
2. T1 Mapping and Survival in Systemic Amyloidosis
- AHA Young Investigator Award, AHA, Dallas, USA, Nov 2013
3. Assessment of Organ Dysfunction in Systemic AL Amyloidosis using Equilibrium MRI to
calculate Extracellular Volume Fraction
- EuroCMR, Florence, Italy, May 2013
4. Multi-Organ ECV as Measured by Eq-MRI in Systemic Amyloidosis
- SCMR, San Francisco, USA, Feb 2013
5. Cardiac Disease in Systemic Amyloidosis as Measured by Eq-CMR
- Young Investigator Award, International Amyloidosis Symposium, Groningen, Holland, May
2012
6. Pre-Contrast ShMOLLI T1 mapping in Cardiac AL Amyloidosis
- SCMR, Orlando, USA, Feb 2012
16.9.2 Poster Presentations:
1. Cardiac Disease in Systemic AL Amyloidosis as measured by EQ-CMR
- SCMR, Orlando, Feb 2012
2. Cardiac Involvement in Systemic AL Amyloidosis as measured by EQ-CMR
- BCS, Manchester, June 2012
Page 150 of 150
16.9.3 Named-author Abstracts Presented by Others:
1. Mahmood S, Venner CP, Lane T, Rannigan L, Foard D, Pinney J, Banypersad SM, Dungu J,
Whelan C, Lachmann HJ, Gillmore JD, Hawkins PN, Wechalekar A, “Continuous Therapy
with Lenalidomide Correlates with Improved Progression Free Survival in Heavily Pre-
Treated Patients with AL Amyloidosis.” Blood (2012); 120(21), 2978
2. Venner CP, Lane T, Foard D, Rannigan L, Mahmood S, Gibbs SDJ, Pinney J, Banypersad SM,
Dungu J, Whelan C, Lachmann H, Gillmore JD, Hawkins PN, Wechalekar A, “A Matched
Comparison of Cyclophosphamide, Bortezomib and Dexamethasone (CVD) Versus
Cyclophosphamide, Thalidomide and Dexamethasone (CTD) in the Treatment of Mayo
Cardiac Stage III Patients with AL Amyloidosis.” Blood (2012); 120(21), 2966
3. Lane T, Rannigan L, Foard D, Wechalekar A, Gibbs S, Pinney J, Venner CP, Banypersad SM,
Lachmann H, Hawkins PN, Gillmore JD, “ALchemy - A Large Prospective 'Real World' Study
of Chemotherapy in AL Amyloidosis” Blood (2011); 118(21), 453
4. Pinney JH, Lachmann HJ, Gillmore JG, Wechalekar A, Gibbs SD, Sattianayagam P,
Banypersad SM, Dungu J, Wassef N, McCarthy CA, Hawkins PN, Whelan CJ. Senile Systemic
Amyloidosis: A common cause of heart failure in the elderly? Heart (2011); 97(Suppl 1), 59-
60